AU2020274440A1

AU2020274440A1 - Portable machine tool

Info

Publication number: AU2020274440A1
Application number: AU2020274440A
Authority: AU
Inventors: Takahiro Fujimori; Kiyoshi IDOTA; Toshiki Yokoyama
Original assignee: Nitto Kohki Co Ltd
Current assignee: Nitto Kohki Co Ltd
Priority date: 2019-05-10
Filing date: 2020-03-23
Publication date: 2021-11-04
Anticipated expiration: 2040-03-23
Also published as: JP7213340B2; DE112020002313T5; AU2020274440B2; WO2020230454A1; JPWO2020230454A1; CN113747990A

Abstract

[Problem] To prevent a lighting device from being affected by chips even when the device is configured to illuminate a work tool from the side. [Solution] A portable machine tool 1 is provided with a lighting device 46 inside a machine tool body 10. The lighting device 46 is composed of an LED element 52 and a light guide member 54. Light L of the lighting device 46 is emitted from a window 64 of a lower surface 10a of the machine tool body 10. The light L is emitted obliquely toward a side surface (reflection surface) 12a of a forward side of a fixation section 12, and is reflected at the side surface 12a to illuminate the periphery of a distal end section 36a of a center pin 36 of an annular cutter 16.

Description

Description Title of Invention: Portable Machine Tool Technical Field:

[0001] The present invention relates to portable machine tools and, more particularly, to a portable machine tool having an illuminating device illuminating the distal end of a working tool. Background Art:

[0002] Portable machine tools are carried by workers to worksites to be used there. Portable machine tools may be used in various environments, sometimes in dark rooms or environments where there is no external lighting at night. In order to allow use in such dark environments, there have been developed portable machine tools equipped with an illuminating device. Patent Literatures 1 and 2, for example, disclose portable drilling machines of the type in which an illuminating device is provided on a securing unit having an electromagnet for securing a portable machine tool to a workpiece, thereby allowing an annular cutter to be illuminated from a lateral direction. The annular cutter has an annular blade portion and a center pin extending along the rotation axis of the blade portion. The annular cutter is positioned by abutting the distal end of the center pin against the center of a to-be-machined region of a workpiece. Therefore, when the workplace is dark, it is necessary to illuminate brightly the distal end of the center pin and surroundings thereof. When light is applied from above, the distal end of the center pin is hidden behind the blade portion, so that it is difficult to apply light to the distal end of the center pin. In the Patent Literatures 1 and 2, the illuminating device is provided on the securing unit to apply light to the center pin from a lateral direction, thereby allowing the distal end of the center pin and surroundings thereof to be illuminated brightly without being hidden behind the blade portion. Citation List: Patent Literature:

[0003] Patent Literature 1: Japanese Patent No. 4474155 Patent Literature 2: United States Patent No. 9889508 Summary of Invention: Technical Problem:

[0004] When a machining operation is performed with a working tool such as an annular cutter, machining swarf produced by machining are scattered laterally from the working tool by the rotation thereof. It is also the case that elongated machining swarf adhering to the working tool may rotate together with the working tool. When the illuminating device is provided on the securing unit at a position lateral to the working tool, as has been stated above, machining swarf may hit the illuminating device. Consequently, the light exit surface of the illuminating device may be damaged or stained, resulting in becoming unable to apply sufficient light.

[0005] Accordingly, it is an object of the present invention to provide a portable machine tool capable of illuminating a working tool from a lateral direction by an illuminating device, and yet, capable of preventing the illuminating device from being affected by machining swarf. Solution to Problem:

[0006] That is, the present invention provides a portable machine tool including the following: a machine tool body having a power section and a tool mounting part rotationally driven by the power section; a reflecting surface disposed to face a working tool at a position lateral to the working tool, the working tool being configured to be mounted to the tool mounting part and extend to the outside of the machine tool body; and an illuminating device disposed to emit light obliquely to the reflecting surface so that light reflected by the reflecting surface illuminates the distal end of the working tool and surroundings thereof.

[0007] In the above-described portable machine tool, light reflected by the reflecting surface, which is located at a position lateral to the working tool, illuminates the surroundings of the distal end of the working tool. In other words, the distal end of the working tool is illuminated from a lateral direction. Therefore, the distal end of the working tool is not hidden behind other portions of the working tool, and there is no possibility that the distal end of the working tool will not be illuminated sufficiently. In addition, because reflected light is used for illumination, the illuminating device need not be disposed at a position lateral to the working tool but can be disposed at a position sufficiently far away from the distal end of the working tool and the workpiece so that the illuminating device can hardly be affected by machining swarf. It is therefore possible to prevent the illuminating device from being damaged or stained by machining swarf produced during machining operation.

[0008] In addition, the tool mounting part may be configured to be movable up and down, and the portable machine tool may further include a securing unit located underneath the machine tool body, the securing unit being configured to secure the machine tool body to a workpiece. Further, the illuminating device may be disposed in the machine tool body so that light from the illuminating device exits from a lower surface of the machine tool body.

[0009] In this case, the reflecting surface may be configured to be a part of a side surface of the securing unit.

[0010] With the above-described arrangement, it is unnecessary to separately provide a member having a reflecting surface and hence possible to simplify the structure.

[0011] Further, the arrangement maybe as follows. The tool mounting part is located at a position forward of the securing unit. The illuminating device is disposed at a position offset in one of right and left directions with respect to a working tool mounted to the tool mounting part to emit light downwardly rearward in the other of the right and left directions to apply the light to the reflecting surface.

[0012] The above-described positional relationship among the tool mounting part, the forward side surface of the securing unit as a reflecting surface, and the illuminating device enables light emitted from the illuminating device to favorably illuminate the surroundings of the distal end of the working tool.

[0013] The illuminating device maybe configured to emit light diffusely so that light reflected by the reflecting surface is diffusely applied to the distal end of the working tool and surroundings thereof. The degree of diffusion of light may be appropriately designed according to need.

[0014] Further, the arrangement maybe as follows. The working tool is an annular cutter having an annular blade portion and a center pin extending in an up-down direction through the center of the blade portion. The distal end of the center pin is the distal end of the working tool.

[0015] The center pin extends downward beyond the annular blade portion to perform positioning of the annular blade portion with respect to a to-be-machined region of a workpiece. In this regard, light emitted from the illuminating device is reflected by the reflecting surface at a position lateral to the working tool so that the reflected light is applied to the distal end of the center pin. Accordingly, the distal end of the center pin is not hidden behind the blade portion but sufficiently irradiated with light.

[0016] Further, the illuminating device maybe configured to have alight source and a light guide member directing light emitted from the light source toward the reflecting surface.

[0017] The use of alight guide member facilitates designing the illuminating device so that light from the light source is directed to the reflecting surface in a favorable condition.

[0018] An embodiment of a portable machine tool according to the present invention will be explained below on the basis of the accompanying drawings. Brief Description of Drawings:

[0019] Fig. 1 is a side view of a portable machine tool according to an embodiment of the present invention. Fig. 2 is a top view of the portable machine tool shown in Fig. 1. Fig. 3 is a sectional view taken along the line III-III in Fig. 2. Fig. 4 is a sectional view taken along the line IV-IV in Fig. 2.

Fig. 5 is a sectional view taken along the line V-V in Fig. 2. Fig. 6 is a perspective view of an illuminating device of the portable machine tool in Fig. 1, as seen from obliquely above. Fig. 7 is a perspective view of the illuminating device in Fig. 6 as seen from obliquely below. Fig. 8 is a front view of the illuminating device in Fig. 6. Fig. 9 is a left-hand side view of the illuminating device in Fig. 6. Fig. 10 is a perspective view of a forward portion of the portable machine tool in Fig. 1, as seen from obliquely below. Fig. 11 is a perspective view of the forward portion of the portable machine tool in Fig. 1, as seen from obliquely above. Description of Embodiments:

[0020] A portable machine tool 1 according to an embodiment of the present invention includes, as shown in Figs. 1 and 2, a machine tool body 10, a securing unit 12 secured to the lower side of the machine tool body 10, and a battery 14 removably attached to the rear of the machine tool body 10. As shown in Fig. 3, the machine tool body 10 includes therein a working tool mounting part 18 for removably mounting an annular cutter 16 (working tool) at a position forward of the securing unit 12, and a power section 19 for rotationally driving the working tool mounting part 18. The power section 19 mainly comprises a motor 20 and a gear mechanism 22 comprising a plurality of gears. The working tool mounting part 18 is configured to move up and down in response to pivoting of a lever 24 attached to a side of the machine tool body , thereby allowing the annular cutter 16 to be moved up and down. Thesecuring unit 12 includes a first electromagnet 28 having a ring-shaped first coil 26, and a second electromagnet 32 similarly having a ring-shaped second coil 30. When the first coil 26 and the second coil 30 are supplied with electric power in a state where the portable machine tool 1 is placed on a magnetic material, the machine tool body 10 is secured to the magnetic material by magnetic holding force generated by the first electromagnet 28 and the second electromagnet 32. The portable machine tool 1 is a drilling machine configured to drill a workpiece M made of a magnetic material by pressing the annular cutter 16 being rotated by the power section 19 against the workpiece M in a state where the machine tool body 10 is secured to the workpiece M by the first electromagnet 28 and the second electromagnet 32. The annular cutter 16 has an annular blade portion 34 and a center pin 36 extending in an up-down direction through the center of the annular blade portion 34.

[0021] As shown in Fig. 1, the machine tool body 10 has the following arranged on a side thereof: a motor drive switch 38 for starting the drive of the motor 20; a motor stop switch 40 for stopping the drive of the motor 20; and an electromagnet switch 42 for starting and stopping the drive of the first electromagnet 28 and the second electromagnet 32. The machine tool body 10 further has an illumination switch 44 on the side thereof for turning on and off an illuminating device 46 (described later). These switches 38, 40, 42 and 44 are all momentary switches, which maintain an ON state only as long as a user is pressing the same and which return to an OFF state when released from the user's hand.

[0022] As shown in Fig. 3, the securing unit 12 is further equipped with a first magnetic sensor 48 and a second magnetic sensor 50. The first magnetic sensor 48 is disposed at a position above the first electromagnet 28 to measure a magnetic flux density around the first electromagnet 28. The second magnetic sensor 50 is disposed at a position above the second electromagnet 32 to measure a magnetic flux density around the second electromagnet 32. The portable machine tool 1 is configured to control electric power to be supplied to the first electromagnet 28 and the second electromagnet 32 and to determine whether or not necessary and sufficient magnetic holding force has been obtained on the basis of output values from the first magnetic sensor 48 and the second magnetic sensor 50 and further to display the result of determination on an LED display unit.

[0023] The illuminating device 46 is, as shown in Figs. 4 and 5, disposed in the machine tool body 10 at a position offset in the left direction with respect to the annular cutter 16 as seen from the front (leftward as seen in Figs. 5 and 8). The illuminating device 46 has an LED device 52 as a light source, and a light guide member 54 formed of a transparent resin material. The light guide member 54 has, as shown in Figs. 6 to 9, an insertion hole 56 into which the LED device 52 is inserted. The insertion hole 56 has a bottom surface formed as an inclined light entrance surface 58. Light emitted from the LED device 52 enters the light guide member 54 mainly through the light entrance surface 58. The light entrance surface 58 as a whole is inclined downward toward the front of the portable machine tool 1 (rightward as seen in Figs. 4 and 9) and at the same time toward the left as seen from the front (leftward as seen in Figs. 5 and 8). The diffusion of light entering the light guide member 54 can be suppressed to a certain extent by forming the light entrance surface 58 to be slightly convex upward toward the LED device 52. Light entering the light guide member 54 through the light entrance surface 58 exits from a light exit surface 60 which is a bottom surface of the light guide member 54. The light exit surface 60 is a larger surface than the light entrance surface 58 and inclined in a direction opposite to that of the light entrance surface 58. That is, the light exit surface 60 is inclined downward toward the rear (leftward as seen in Figs. 4 and 9) and at the same time toward the right as seen from the front (rightward as seen in Figs. 5 and 8).

[0024] As shown in Figs. 4, 5, 10 and 11, light L emitted from the illuminating device 46 passes through a transparent cover 62 attached to the machine tool body 10 and exits through a window 64 in a lower surface 10a of the machine tool body 10. Becausethe light entrance surface 58 and the light exit surface 60 are inclined as described above, light emitted from the LED device 52 is refracted by the light entrance surface 58 and the light exit surface 60. Light L exiting from the light exit surface 60 travels in a downwardly rightward and rearward direction while being diffused to a certain extent, and is applied to a forward side surface 12a of the securing unit 12. The side surface 12a faces the annular cutter 16 at a position lateral to the annular cutter 16, which extends to the outside of the machine tool body 10. Consequently, the light L reflected by the side surface 12a is applied diffusely to a distal end 36a of the center pin 36 of the annular cutter 16 and the surroundings of the distal end 36a. That is, the portable machine tool 1 is designed so that light L emitted from the illuminating device 46 is applied obliquely downward to the side surface 12a of the securing unit 12, which functions as a reflecting surface, and that the light L reflected by the side surface 12a illuminates the distal end 36a of the center pin 36 of the annular cutter 16 and the surroundings of the distal end 36a. With this arrangement, even when the distal end 36a of the center pin 36 is in abutting contact with a to-be-machined region of a workpiece M, the distal end 36a and surroundings thereof are illuminated brightly without being hidden behind the annular cutter 16. In addition, the illuminating device 46 is located at a position above the to-be-machined region; therefore, there is no danger of the light exit surface 60 of the light guide member 54 or the cover 62 being damaged or stained by machining swarf produced during drilling with the annular cutter 16.

[0025] Although an embodiment of the present invention has been described above, the present invention is not limited to the described embodiment. For example, the present invention may be applied to a machine tool using a drill, for example, instead of the annular cutter as a working tool. The drill point angle is usually 120 degrees; therefore, when a large-diameter drill, in particular, is used, it may be impossible to illuminate the distal end of the drill if light is applied from above. Even in such a case, the arrangement of the present invention makes it possible to illuminate the distal end of the drill. The securing unit for securing the tool body is not limited to the one using an electromagnet. For example, the securing unit may use magnetic adhesion by a permanent magnet, and it is also possible to use vacuum adhesion by a vacuum device. The securing unit may also be configured to secure the tool body mechanically using a vise or the like. Alternatively, the present invention may be a hand-held machine tool having no securing unit, which is used by being held by a user. Further, the reflecting surface does not need to be a side surface of the securing unit. For example, a part of the machine tool body may be extended to a position lateral to the working tool to form a reflecting surface. Alternatively, another member having a surface to be a reflecting surface may be attached to the machine tool body or the securing unit. The light guide member of the illuminating device is not limited to the one using the above-described configuration but may be formed by combining together a plurality of optical components, e.g. lenses. It is also possible to use an optical fiber to constitute the light guide member. Alternatively, the illuminating device may be configured to apply light from a light source directly to the reflecting surface without having a light guide member. Further, a plurality of illuminating devices may be arranged to illuminate the distal end of the working tool from a plurality of directions. Although the foregoing embodiment uses a battery as a power source, the portable machine tool may be connected to an external power source, e.g. an AC power source. List of Reference Signs:

[0026] 1: portable machine tool 10: machine tool body 10a: lower surface 12: securing unit 12a: side surface (reflecting surface) 14: battery 16: annular cutter (working tool) 18: working tool mounting part (tool mounting part) 19: power section 20: motor 22: gear mechanism 24: lever 26: first coil 28: first electromagnet

: second coil 32: second electromagnet 34: blade portion 36: center pin 36a: distal end 38: motor drive switch : motor stop switch 42: electromagnet switch 44: illumination switch 46: illuminating device 48: first magnetic sensor : second magnetic sensor 52: LED device (light source) 54: light guide member 56: insertion hole 58: light entrance surface : light exit surface 62:cover 64: window L: light M: workpiece

Claims

Claims 1. A portable machine tool comprising: a machine tool body having a power section and a tool mounting part rotationally driven by the power section; a reflecting surface disposed to face a working tool at a position lateral to the working tool, the working tool being configured to be mounted to the tool mounting part and extend to an outside of the machine tool body; and an illuminating device disposed to emit light obliquely to the reflecting surface so that light reflected by the reflecting surface illuminates a distal end of the working tool and surroundings thereof.
2. The portable machine tool of claim 1, wherein the tool mounting part is movable up and down; and wherein the portable machine tool further comprises a securing unit located underneath the machine tool body, the securing unit being configured to secure the machine tool body to a workpiece.
3. The portable machine tool of claim 2, wherein the illuminating device is disposed in the machine tool body so that light from the illuminating device exits from a lower surface of the machine tool body.
4. The portable machine tool of claim 2 or 3, wherein the reflecting surface is a part of a side surface of the securing unit.
5. The portable machine tool of claim 4, wherein the tool mounting part is located at a position forward of the securing unit; and wherein the illuminating device is disposed at a position offset in one of right and left directions with respect to a working tool mounted to the tool mounting part to emit light downwardly rearward in an other of the right and left directions to apply the light to the reflecting surface.
6. The portable machine tool of any one of claims 1 to 5, wherein the illuminating device emits light diffusely so that light reflected by the reflecting surface is applied diffusely to the distal end of the working tool and surroundings thereof.
7. The portable machine tool of any one of claims 1 to 6, wherein the working tool is an annular cutter having an annular blade portion and a center pin extending in an up-down direction through a center of the blade portion, and wherein a distal end of the center pin is the distal end of the working tool.
8. The portable machine tool of any one of claims 1 to 7, wherein the illuminating device has a light source and a light guide member directing light emitted from the light source toward the reflecting surface.

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