JP2013111701A - Portable cutting machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress an amount of use of water sprayed onto a disk cutter.SOLUTION: A portable cutting machine 10 is used to drive a disk cutter 28 by a driving source, such as an engine, to cut a workpiece. Water is jetted to the disk cutter 28 from a nozzle 37 for cooling the disk cutter 28 and suppressing production of powdered chips. When the disk cutter 28 comes in contact with the workpiece, the contact state is determined based on signals from distortion gauges 53a and 53b, which causes water to jet out of the nozzle 37. When the disk cutter 28 breaks its contact, water supply to the nozzle 37 is stopped.

Description

  The present invention relates to a portable cutting machine that rotates a disk cutter and cuts a work material with the disk cutter.

  A portable cutting machine is used for scoring and cutting stone or concrete as a work material by a disk cutter. The portable cutting machine is equipped with a drive source such as an engine or an electric motor, and the disk cutter is rotationally driven by the drive source. When performing a cutting operation using a portable cutting machine, water is supplied to the disc cutter in order to cool the disc cutter during the cutting operation and to suppress generation of dust from the work material. A water injection device for supplying water has a nozzle for injecting water to a disk cutter and a joint connected to a water supply source such as a water supply or a water tank, and the nozzle is connected to the joint by a water supply hose.

  An open / close valve that opens and closes the flow path is provided in the cutting machine to switch between the state where the water from the water supply source communicates with the nozzle and the state where the communication is blocked. The valve is operated and water is jetted from the nozzle to the disc cutter. If the operator operates the switching valve to inject water from the nozzle and then operates the portable cutting machine to perform the work of cutting the work material, the water will continue until the cutting work is performed. Will be ejected from the nozzle. In a portable cutting machine in which the on-off valve is operated manually, water is continuously ejected from the nozzle even when the engine is stopped unless the on-off valve is operated. Therefore, Patent Document 1 discloses a cutting machine that supplies a water flow to a manual on-off valve by an operation signal of the engine when the engine is driven to rotate, and stops the water flow supply to stop the engine. Yes.

JP 2006-198765 A

  If the water flow is supplied to the cutting machine only when the engine is driven, the water flow is stopped when the engine is stopped without operating the manual switching valve. It is possible to prevent consumption of fresh water. However, it is often the case that the engine continues to be driven even when the cutting operation is not performed, and water is continuously supplied to the disc cutter even when the cutting operation is not actually performed. Will be consumed.

  An object of the present invention is to suppress the amount of water used for spraying a disc cutter.

  The portable cutting machine of the present invention is a portable cutting machine that drives a disk cutter by a drive source incorporated in a cutting machine body, the nozzle for spraying water onto the disk cutter, and the disk cutter is a work material Contact detection means for detecting contact with the nozzle and control means for controlling supply of water to the nozzle based on a signal from the contact detection means.

  In the portable cutting machine according to the present invention, the contact detection means detects a stress applied to the arm. In the portable cutting machine of the present invention, a strain gauge that detects stress applied to the arm by contact between the disc cutter and a work material is provided on an arm on which the disc cutter is rotatably supported. The supply of water to the nozzle is controlled based on the signal.

  The portable cutting machine according to the present invention is characterized in that the contact detecting means detects a load applied to the rotating body. The portable cutting machine of the present invention detects a load applied to the rotating body by contact between the disk cutter and the work material on the rotating body in the power transmission system that transmits the rotational torque of the drive source to the disk cutter. A torque gauge is provided, and water supply to the nozzle is controlled based on a signal from the torque gauge.

  In the portable cutting machine of the present invention, a first strain gauge is provided on one side in the width direction of the arm, a second strain gauge is provided on the other side in the width direction, and the disk cutter is in contact with the horizontal surface of the work material. When the respective strain gauges detect that the stress direction applied to both sides of the arm is reversed to the tensile stress and the compressive stress, and the disk cutter comes into contact with the vertical surface of the work material, When both the strain gauges detect compressive stress, water is supplied to the nozzle. In the portable cutting machine of the present invention, an opening / closing valve for opening and closing a flow path of the supply hose is provided in a supply hose for supplying water supplied from a water supply source to the nozzle, and the disc cutter comes into contact with the work material. The on-off valve is opened when it is in contact, and the on-off valve is closed when not in contact. The portable cutting machine of the present invention has a pump for supplying water to the nozzle, and drives the pump when the disc cutter comes into contact with the work material, and drives the pump when not in contact with the work material. It is characterized by stopping.

  In the present invention, when the disk cutter of the portable cutting machine is brought into contact with the work material to perform a cutting operation, water is sprayed from the nozzle to the disk cutter, and water injection is performed when the disk cutter is separated from the work material. Stopped. Thereby, even if the disk cutter is driven to rotate, water injection is stopped when the cutting operation is stopped, and the amount of water used can be greatly reduced.

It is a front view which shows the portable cutting machine which is one embodiment of this invention. It is an AA line expanded sectional view in FIG. It is the BB line expanded sectional view in FIG. It is a top view of FIG. It is a top view of the on-off valve shown by FIG. It is CC sectional view taken on the line in FIG. It is sectional drawing which shows the on-off valve in a flow-path open state. (A) is a front view which shows the portable cutting machine in the state which is cutting the horizontal surface of a work material, (B) is the portable cutting machine in the state which is cutting the vertical surface of a work material FIG. FIG. 2 is an enlarged sectional view taken along line DD in FIG. 1. It is a block diagram which shows a water injection control circuit. It is a stress state table | surface which shows the stress state added to an arm at the time of a cutting operation. It is a front view which shows the portable cutting machine which is other embodiment. It is the EE line expanded sectional view in FIG. (A) is the FF sectional view taken on the line in FIG. 13, (B) is the GG sectional view in FIG. (A) is a top view which shows the on-off valve of a modification, (B) is the HH sectional view taken on the line of (A), (C) It is a top view which shows the on-off valve in a channel open state, (D) is the II sectional view taken on the line of (C).

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The portable cutting machine 10 has a main body case 11 as a main body of a cutting machine, and an engine 12 as a drive source is incorporated in the main body case 11. As shown in FIG. 2, the engine 12 includes crankcases 14 a and 14 b on which a crankshaft 13 is rotatably mounted, and a cylinder 16 in which a piston 15 is reciprocally incorporated. The piston 15 is connected to the crankshaft 13 by a connecting rod 17, and the crankshaft 13 is rotationally driven by the reciprocating motion of the piston 15. The air-fuel mixture is supplied to the combustion chamber 18 in the cylinder 16 from an intake port (not shown), and the combustion exhaust gas is discharged to the outside from an exhaust port (not shown). In order to start the engine 12, a recoil starter 19 is provided in the crankcase 14a, and the recoil starter 19 is connected to one protruding end of the crankshaft 13. The cylinder 16 is provided with a spark plug 20 for igniting the air-fuel mixture supplied into the combustion chamber 18.

  A centrifugal clutch 21 is attached to the other protruding end of the crankshaft 13. The centrifugal clutch 21 has a rotor 22 fixed to the crankshaft 13 and a clutch drum 23 in which the rotor 22 is accommodated, and a plurality of clutch shoes mounted on the rotor 22 in a swingable manner in the clutch drum 23. 24 is incorporated. When the rotational speed of the crankshaft 13 is increased to the working rotational speed, the clutch shoe 24 comes into close contact with the inner peripheral surface of the clutch drum 23 by centrifugal force against the spring force, and the rotation of the crankshaft 13 causes the clutch drum 23 to rotate. Is transmitted to.

  An arm 25 is attached to the crankcase 14b. As shown in FIG. 1, a driven-side rotary shaft 27 to which a driven-side pulley 26 is fixed is rotatably attached to the distal end portion of the arm 25, and a disk cutter 28 is attached to the rotary shaft 27. ing. As shown in FIG. 2, a drive-side pulley 29 that is mounted on the crankshaft 13 via a bearing is attached to the clutch drum 23. A belt 30 is stretched between the driving pulley 29 and the driven pulley 26, and when the rotation of the crankshaft 13 is transmitted to the clutch drum 23, the pulleys 26 and 29 and the belt 30 are passed through. Thus, the rotational torque of the crankshaft 13 is transmitted to the disk cutter 28. The crankshaft 13 to the rotary shaft 27 constitute a power transmission system for transmitting engine power to the disk cutter 28.

  As shown in FIGS. 1 and 4, a rear handle 31 is attached to the rear portion of the main body case 11 so as to protrude rearward, and a front handle 32 is attached to the front portion of the main body case 11 so as to cross the main body case 11. It has been. When an operator cuts a work material with the portable cutting machine 10, the user holds the rear handle 31 with one hand and the front handle 32 with the other hand to lift the portable cutting machine 10. Become. When the portable cutting machine 10 is not used, the portable cutting machine 10 is disposed on the base surface S at the leg portions 33 and 34 provided at the front and rear of the main body case 11. Under this state, the disk cutter 28 does not contact the base surface S. The rear handle 31 is provided with a throttle lever 35 for adjusting the rotational speed of the engine 12.

  A blade cover 36 is attached to the arm 25 as shown in FIGS. 1 and 4, and the rear side of the disk cutter 28 is covered by the blade cover 36. As shown in FIG. 3, two nozzles 37 are attached to the blade cover 36 so as to face each other via the disk cutter 28. An ejection port 38 is provided at the tip of each nozzle 37, and water is ejected from the respective ejection port 38 onto the surface of the disk cutter 28. As a result, the disc cutter 28 being cut is cooled and the scattering of dust generated during cutting is suppressed. Both nozzles 37 are connected to each other by a connection hose 39. In order to supply water to each nozzle 37, a supply hose 41 is connected to the nozzle 37 as shown in FIG.

  As shown in FIG. 1, the supply hose 41 is connected to an on-off valve 42 attached to the main body case 11. As shown in FIGS. 5 to 7, the on-off valve 42 has a valve housing 45 in which an inflow port 43 and an outflow port 44 are formed, and a supply hose 41 is attached to the outflow port 44 by a joint 46. On the other hand, a water supply hose (not shown) connected to a water supply source such as a water supply or a water tank is connected to the joint 47 attached to the inflow port 43.

  A valve body 49 for opening and closing a communication passage 48 for communicating the inflow port 43 and the outflow port 44 is incorporated in the valve housing 45 so as to be freely opened and closed. The valve housing 45 incorporates a coil spring 51 for energizing the spring force in the direction in which the valve body 49 closes the communication passage 48. The valve body 49 is driven against the spring force and the communication passage 48 is opened. A solenoid 52 for opening is provided in the valve housing 45. As described above, the on-off valve 42 is an electromagnetic valve that is opened and closed by a drive signal applied to the solenoid 52. FIG. 6 shows a state where the valve body 49 closes the communication path 48, and FIG. 7 shows a state where the drive signal is applied to the solenoid 52 and the valve body 49 opens the communication path 48.

  The cutting work including the creasing work for the work material W by the portable cutting machine 10 is shown in the case where the disk cutter 28 is brought into contact with a horizontal plane as shown in FIG. 8A and in the case shown in FIG. 8B. In some cases, the vertical surface is brought into contact with the vertical surface, and the inclined surface is further brought into contact. In any work mode, when a cutting operation is performed, stress is applied to the arm 25 by a load applied to the disc cutter 28, and a load is applied to the power transmission system for transmitting the power of the crankshaft 13 to the disc cutter 28. Torque will be applied.

  FIG. 9 shows a cross section of the arm 25. The arm 25 has an arm base portion 25a and an arm cover portion 25b attached to the arm base portion 25a. A first strain gauge 53a is attached to the upper side of the arm 25 in the width direction, that is, one side, and a second strain gauge 53b is attached to the lower side of the arm 25 in the width direction, that is, the other side. In each of the strain gauges 53a and 53b, a stretching strain is generated according to the stress applied to the arm 25, and the electric resistance of the strain gauges 53a and 53b changes. Due to the change in the resistance value, the disk cutter 28 is in contact with the work material W as shown in FIG. 8 to perform the cutting operation, or the disk cutter 28 is turned into the work material W as shown in FIG. It is possible to detect whether there is a non-working state that is not in contact. When it is detected that the disc cutter 28 is in a working state in contact with the work material W, the on-off valve 42 opens the communication passage 48 and water is ejected from the nozzle 37. On the other hand, when it is detected that there is no working state, the on-off valve 42 closes the communication path 48 and the ejection of water is stopped.

  Therefore, water is jetted to the disk cutter 28 only when the cutting work is performed on the workpiece W by the disk cutter 28, and even when the engine 12 is driven and the disk cutter 28 is rotating, Water is not sprayed from the nozzle 37 when no cutting operation is performed. Thereby, the usage-amount of water can be reduced significantly. Furthermore, since the water injection and the water injection stop are not manually operated, it is possible to prevent useless ejection of water due to the operator forgetting to stop the water injection.

  When the disk cutter 28 is brought into contact with the work material W, tensile stress or compressive stress is applied to the strain gauges 53a and 53b provided on the side portions of the arm 25, so that the strain gauges 53a and 53b that undergo strain deformation according to the stress. The contact state can be detected by a signal from. In the illustrated case, two strain gauges 53a and 53b are provided. However, even in a single gauge configuration in which only one strain cage is provided, a contact state is detected according to a change in stress applied to the arm 25. be able to. In such a case, zero adjustment is performed with the resistance value of the strain gauge in a state where the disk cutter 28 is not in contact with the work material W, that is, when there is no work, as a reference value, and the resistance value of the strain gauge is relative to the reference value. It is possible to determine that the disc cutter 28 is in a contact state when the change is greater than a predetermined contact determination value. On the other hand, as shown in the figure, the contact state detection accuracy can be further improved by adopting a multiple gauge configuration in which two strain gauges 53a and 53b are provided. As shown by solid lines in FIG. 9, the respective strain gauges 53 a and 53 b are attached to the arm base 25 a of the arm 25.

  As described above, the stress change applied to the arm 25 is detected by the strain gauge that the disc cutter 28 is in contact with the workpiece W. However, since the arm 25 is elastically deformed, the deformation of the arm 25 is displaced. The contact with the disk cutter 28 may be detected by measuring with a meter.

  FIG. 10 is a block diagram showing a water injection control circuit for controlling the water injection of the portable cutting machine 10, and detection signals are sent from the respective strain gauges 53a, 53b to the controller. A drive signal is sent from the controller 54 to the solenoid 52 of the on-off valve 42. The controller 54 has a calculation unit that performs calculation processing based on the signals from the strain gauges 53a and 53b to determine whether or not to send a drive signal to the on-off valve 42 due to the change.

  FIG. 11 is a stress state table showing changes in stress applied to the respective strain gauges 53a and 53b during no work and during work. When no work is performed, tensile stress is applied to the first strain gauge 53a by the weight of the arm 25, and compressive stress is applied to the second strain gauge 53b. As shown in FIG. 8A, when the disc cutter 28 is brought into contact with the horizontal surface of the work material W, compressive stress is applied to the first strain gauge 53a, and tension is applied to the second strain gauge 53b. Stress will be applied. Thus, when the disc cutter 28 is brought into contact with the horizontal plane, the first strain gauge 53a is reversed from the state in which the tensile stress is applied during no operation to the state in which the compressive stress is applied, and the second strain gauge 53b is not applied. It reverses from the state in which the compressive stress at the time of work is applied to the state in which the tensile stress is applied.

  On the other hand, when the disc cutter 28 is brought into contact with the vertical surface of the work material W as shown in FIG. 8B, compressive stress is applied to the respective strain gauges 53a and 53b. At this time, the first strain gauge 53a reverses from the state in which the tensile stress is applied during no operation to the state in which the compressive stress is applied, and the second strain gauge 53b has a greater compressive stress during the no operation. As described above, when the disk cutter 28 is brought into contact with the vertical surface, both the strain gauges 53a and 53b are in a state where compressive stress is applied to the arm 25.

  As shown in the figure, when a multi-gauge configuration is used, a contact state is detected with higher accuracy than a single-gauge configuration based on a stress reversal state or reversal state signal detected by a plurality of strain gauges 53a and 53b. be able to.

  FIG. 12 is a front view showing a portable cutting machine 10 according to another embodiment of the present invention. 13 is an enlarged sectional view taken along line EE in FIG. 12, FIG. 14A is a sectional view taken along line FF in FIG. 13, and FIG. 14B is a sectional view taken along line GG in FIG. is there.

  As described above, when a cutting operation is performed, load torque is applied to the power transmission system for transmitting the power of the crankshaft 13 to the disc cutter 28. Therefore, the load applied to the power transmission system is the determination value, that is, Whether or not the disc cutter 28 has contacted the work material W can be detected based on whether or not the threshold value has been exceeded. Therefore, in the portable cutting machine 10 shown in FIGS. 12 to 14, the opening and closing of the on-off valve 42 is controlled according to the load torque applied to the power transmission system.

  As shown in FIG. 13, the rotating shaft 27 on the driven side as a rotating body is rotatably supported by a cylindrical portion 56 provided on the arm base 25a via a bearing 57, and is attached to one end portion of the rotating shaft 27. A disk cutter 28 is attached. Foil washers 58 and 59 are pressed from both sides at the radial center of the disc cutter 28, and a washer 61 that contacts the outer foil washer 59 is fixed by a bolt 62. A driven pulley 26 is fixed to the other end of the rotating shaft 27 by a bolt 63.

  A torque gauge 64 is attached to the outer peripheral surface of the rotary shaft 27. When a torque is applied to the rotary shaft 27 according to the load torque applied to the power transmission system, the torque gauge 64 is elastically deformed accordingly, and the electrical resistance changes in the same manner as the strain gauges 53a and 53b. In order to send a detection signal from the torque gauge 64 to the controller 54, output terminals 65 and 66 of the torque gauge 64 are annularly provided on both sides in the axial direction of the torque gauge 64, and the respective outputs are provided. The terminals 65 and 66 are insulated from the outer peripheral surface of the rotating shaft 27. Connection terminals 67 and 68 that contact the respective output terminals 65 and 66 are attached to the cylindrical portion 56, and the output terminals 65 and 66 are connected to the controller 54 by signal lines 67a and 68a.

  The controller 54 controls the water injection to the disc cutter 28 by operating the on-off valve 42 by calculating whether or not the load torque applied to the rotary shaft 27 exceeds the threshold when the disc cutter 28 contacts the work material W. To do. In the portable cutting machine 10 shown in FIGS. 12 to 14, the water injection is controlled according to the load torque of the rotary shaft 27, but a power transmission system such as the crankshaft 13 and the clutch drum 23 is used. As long as the rotating body is configured, load torque applied to members other than the rotating shaft 27 may be detected by the torque gauge 64.

  In this way, it is determined whether or not the disk cutter 28 is in contact with the work material W by adopting a form in which the load torque in the power transmission system is detected instead of the form in which the stress applied to the arm 25 is detected. Can be detected. However, as shown in FIG. 12, similarly to the portable cutting machine 10 shown in FIG. 1, the arm 25 is provided with strain gauges 53a and 53b, and detection signals from the strain gauges 53a and 53b and the torque gauge 64 are received. Each may be sent to the controller 54. Thus, in the embodiment in which the water injection is controlled by the stress applied to the arm 25 and the load torque applied to the power transmission system, the contact of the disk cutter 28 is detected by a signal from one of the strain gauges 53a, 53b and the torque gauge 64. It can be set to either the form which sometimes pours water, or the form which pours water when contact is detected by both signals.

  In the embodiment described above, water injection control is performed by opening and closing the on-off valve 42, and water from a water supply source is always supplied to the joint 47. On the other hand, as shown in FIG. 12, when the hose 70 connected to the discharge port of the water supply pump 69 as a water supply source is connected to the joint 47, the water supply to the nozzle 37 is controlled by turning the water supply pump 69 on and off. Will do. In this embodiment, the opening / closing valve 42 made of an electromagnetic valve is not necessary, and a water supply tank (not shown) is connected to the suction port of the water supply pump 69. However, a manually operated on-off valve may be attached to the main body case 11 without using the on-off valve as a solenoid valve.

  FIG. 15 shows a manually operated on-off valve 42a. A spherical valve body 49a having a communication hole 48a is rotatably provided in the valve housing 45 of the on-off valve 42a, and an operation lever 71 is attached to the valve body 49a. The opening / closing operation of the opening / closing valve 42a is performed by the operator manually operating the operation lever 71. When the operation lever 71 of the on-off valve 42a having the spherical valve body 49a is driven by an actuator (not shown), the solenoid on-off valve 42 is configured so that the valve body 49 is reciprocated linearly by the solenoid 52. Instead, as the actuator-type opening / closing valve 42a for rotating the spherical valve body 49a, the opening / closing valve 42a can be automatically opened / closed by a drive signal.

  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, although the illustrated portable cutting machine uses the engine 12 as a drive source, the present invention can also be applied to a portable cutting machine using an electric motor as a drive source.

DESCRIPTION OF SYMBOLS 10 ... Portable cutting machine, 11 ... Main body case, 12 ... Engine, 13 ... Crankshaft, 14 ... Crankcase, 15 ... Piston, 16 ... Cylinder, 17 ... Connecting rod, 18 ... Combustion chamber, 19 ... Recoil starter, 21 ... centrifugal clutch, 22 ... rotor, 23 ... clutch drum, 24 ... clutch shoe, 25 ... arm, 26 ... pulley, 27 ... rotating shaft, 28 ... disc cutter, 29 ... pulley, 30 ... belt, 31 ... rear handle, 32 ... front handle, 33, 34 ... leg, 35 ... throttle lever, 36 ... blade cover, 37 ... nozzle, 38 ... injection port, 39 ... connection hose, 41 ... supply hose, 42 ... open / close valve, 43 ... inflow port, 44 ... Outlet port, 45 ... Valve housing, 46, 47 ... Joint, 48 ... Communication path, 49 ... Valve body, 51 ... Coil 52 ... Solenoid, 53a ... First strain gauge, 53b ... Second strain gauge, 54 ... Controller, 56 ... Cylindrical part, 57 ... Bearing, 58, 59 ... Wheel washer, 62, 63 ... Bolt, 64 ... Torque Gauge, 65, 66 ... output terminal, 67, 68 ... connection terminal, 69 ... water supply pump.

Claims (8)

A portable cutting machine that drives a disk cutter by a drive source incorporated in the cutting machine body,
A nozzle for injecting water into the disc cutter;
Contact detection means for detecting that the disk cutter has contacted the work material;
A portable cutting machine comprising: control means for controlling supply of water to the nozzle based on a signal from the contact detection means.   The portable cutting machine according to claim 1, wherein the contact detection means detects a stress applied to the arm.   The arm on which the disk cutter is rotatably supported is provided with a strain gauge for detecting the stress applied to the arm by contact between the disk cutter and the work material, and water for the nozzle is based on a signal from the strain gauge. 3. The portable cutting machine according to claim 2, wherein the supply is controlled.   The portable cutting machine according to claim 1, wherein the contact detection means detects a load applied to the rotating body.   The rotating body in the power transmission system that transmits the rotational torque of the drive source to the disk cutter is provided with a torque gauge that detects a load applied to the rotating body due to contact between the disk cutter and the work material, and from the torque gauge 5. The portable cutting machine according to claim 4, wherein the supply of water to the nozzle is controlled based on the signal.   The first strain gauge is provided on one side in the width direction of the arm, the second strain gauge is provided on the other side in the width direction, and the stress applied to both sides of the arm when the disk cutter contacts the horizontal surface of the work material When the respective strain gauges detected that the direction was reversed between tensile stress and compressive stress, and when the disc cutter contacted the vertical surface of the work material, both strain gauges detected compressive stress. 4. The portable cutting machine according to claim 3, wherein water is supplied to the nozzle.   The supply hose that supplies water supplied from the water supply source to the nozzle is provided with an open / close valve that opens and closes the flow path of the supply hose, and the open / close valve is opened when the disc cutter is in contact with the work material. And when not contacting, the said on-off valve is closed, The portable cutting machine of any one of Claims 1-6 characterized by the above-mentioned.   A pump for supplying water to the nozzle is provided, and the pump is driven when the disc cutter comes into contact with the work material, and the drive of the pump is stopped when not in contact with the work material. The portable cutting machine of any one of 1-6.

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