Patent Application
20110056084
The present application relates to subject matter contained in Japanese Patent Application No. 2009-208109, filed on Sep. 9, 2009, and Japanese Patent Application No. 2010-142507, filed on Jun. 23, 2010, all of which are expressly incorporated herein by reference in their entirety.
1. Field of the Invention
The present invention relates to an electric cutting tool, and particularly, the present invention relates to an electric cutting tool in which a cutting depth (depth of cut) or an inclination angle of a circular saw blade is displayed at a position viewable for an operator.
2. Description of the Related Art
Heretofore, an electric cutting tool, including a surface plate, a body portion tiltably mounted on this surface plate and a circular saw blade rotatably provided by driving power from a driver included in the body portion, is known (for example, see Japanese Patent Application Publication No. 8-142001; hereinafter, referred to as “Patent Literature 1”). In a conventional electric cutting tool illustrated in Patent Literature 1, an indicator scale has generally been provided so that a cutting depth of the circular saw blade can be confirmed during an operation. However, since an operator has to confirm this indicator scale by sight, the indicator scale has a problem that it lacks in accuracy. Further, the indicator scale included in the conventional electric cutting tool must convert a circular motion, that is, a rotary motion of the circular saw blade into a linear dimension, that is, a cutting depth. For that reason, intervals of scale marks (measurements) necessarily become imbalanced like the indicator scale disclosed in Patent Literature 1. Therefore, it is hard for the operator to view and confirm the conventional indicator scale, and it is easy to generate an error.
On the other hand, Japanese Patent Application Publication No. 9-268516 (hereinafter, referred to as “Patent Literature 2”) discloses a technique for displaying a cutting depth with high accuracy. Patent Literature 2 discloses a concrete cutter with a display device capable of displaying the cutting depth of a blade. However, this concrete cutter with the cutting depth display device detects movement amounts of two members including an up-and-down arm and a frame, each of which carries out a circular motion, by means of a rack and a pinion; converts an amount of rotation of the pinion into an up-and-down amount of a mounting shaft of the blade; and thereby displays a cutting depth of the blade.
However, the technique disclosed in Patent Literature 2 mentioned above obtains the movement amount of the blade on the basis of the two members including the up-and-down arm and the frame, each of which carries out the circular motion. Thus, such a technique includes a structural problem that an error occurs inevitably. Therefore, even if the conventional techniques disclosed in Patent Literatures 1 and 2 mentioned above are combined, it is impossible to obtain an electric cutting tool capable of displaying a cutting depth and/or an inclination angle of a circular saw blade with high accuracy.
The present invention has been made in order to solve the problem described above, and it is an object of the present invention to provide a new electric cutting tool capable of calculating a cutting depth and an inclination angle of a circular saw blade with high accuracy, and of displaying its calculation result by means of a display section arranged at a position viewable for an operator.
Hereinafter, the present invention will be described. In this regard, reference numerals of the appending drawings are added in parenthesis in order to facilitate understanding of the present invention. However, this does not cause the present invention to be limited in the illustrated forms.
In order to achieve the above object, the present invention is directed to an electric cutting tool. The electric cutting tool (10μ, 10′) according to the present invention includes: a surface plate (11); a body portion (21) tiltably provided on the surface plate (11); and a circular saw blade (41) capable of rotating by means of driving power from a driver (25) provided in the body portion (21). The electric cutting tool (10, 10′) also includes a movement amount measuring section (50, 50′, 50″, 80, 90) for measuring a movement amount of the body portion (21) with respect to the surface plate (11) in response to a tilting action. The electric cutting tool (10, 10′) also includes a calculating section (61) for calculating a cutting depth of the circular saw blade (41) or an inclination angle of the body portion (21) on the basis of the movement amount measured by the movement amount measuring section (50, 50′, 50″, 80, 90). The electric cutting tool (10, 10′) also includes a display section (62) for displaying the cutting depth or the inclination angle of the body portion (21) calculated by the calculating section (61).
In the electric cutting tool (10) according to the present invention, it is preferable that the movement amount measuring section (50, 50′, 50″, 80) includes: a scale section (51, 51′, 51″, 81) installed on any one of the surface plate (11) and the body portion (21), the scale section including scale marks provided at predetermined intervals; and a scale detecting section (52, 52′, 52″, 82) for detecting the scale marks included in the scale section (51, 51′, 51″, 81), the scale detecting section being installed on the other of the surface plate (11) and the body portion (21).
Further, in the electric cutting tool (10) according to the present invention, it is preferable that the scale section is a magnetic scale (51, 51′, 51″) in which the scale marks are recorded as magnetic patterns, and that the scale detecting section is a magnetic detecting head (52, 52′, 52″) for measuring the movement amount of the body portion (21) with respect to the surface plate (11) in response to the tilting action by reading out the scale marks from the magnetic scale and converting a read-out result into an electrical signal.
Further, in the electric cutting tool (10) according to the present invention, it is preferable that the scale section is a rack (81) in which teeth for the scale marks are cut at predetermined intervals, and the scale detecting section is a pinion (82) for measuring the movement amount of the body portion (21) with respect to the surface plate (11) in response to the tilting action by causing the pinion to carry out a rotary motion while engaging with the rack (81) and detecting an amount of rotary motion.
Moreover, in the electric cutting tool (10) according to the present invention, it is preferable that the body portion (21) includes: a gripper (28) used when a tilting operation of the body portion (21) is carried out; and a cover portion (27) that covers an outer circumference of the circular saw blade (41), wherein the display section (62) is installed at a region between the gripper (28) and the cover portion (27).
Furthermore, in the electric cutting tool (10, 10′) according to the present invention, it is preferable that the body portion (21) is configured so that the circular saw blade (41) can be tilted in a direction to be tilted to a side surface of the electric cutting tool, and that the calculating section (61) calculates the cutting depth of the circular saw blade (41) by carrying out correction in accordance with a tilt angle in a direction in which the circular saw blade (41) is to be tilted to the side surface.
Furthermore, in the electric cutting tool (10′) according to the present invention, it is preferable that the movement amount measuring section (90), the calculating section (61) and the display section (62) are integrally installed by means of a casing (64).
Further, in the electric cutting tool according to the present invention (10′), it is preferable that the calculating section (61), the display section (62) and the casing (64) are arranged so as not to protrude from an outline of the body portion (21).
Moreover, in the electric cutting tool (10′) according to the present invention, it is preferable that the electric cutting tool (10′) further includes: a link member (13) for linking the surface plate (11) to the body portion (21), the link member (13) extending along a tilt direction of the body portion (21) from an upper surface of the surface plate (11), that the movement amount measuring section includes an angle sensor (90) for detecting an inclination angle of the link member (13) with respect to the surface plate (11), and that the calculating section (61) calculates the cutting depth of the circular saw blade (41) or the inclination angle of the body portion (21) on the basis of the inclination angle detected by the angle sensor (90).
Furthermore, in the electric cutting tool (10′) according to the present invention, it is preferable that the body portion (21) includes a cover portion (27) that covers an outer circumference of the circular saw blade (41), the cover portion (27) capable of tilting with respect to the surface plate (11) together with the circular saw blade (41), that the movement amount measuring section includes an angle sensor (90) for detecting an inclination angle of the cover portion (27) with respect to the surface plate (11), and that the calculating section (61) calculates the cutting depth of the circular saw blade (41) or the inclination angle of the body portion (21) on the basis of the inclination angle detected by the angle sensor (90).
According to the present invention, it is possible to provide a new electric cutting tool capable of calculating a cutting depth or an inclination angle of a circular saw blade with high accuracy, and of displaying its calculation result by means of a display section arranged at a position viewable for an operator.
The foregoing and other objects, features and advantages of the present invention will become more readily apparent from the following detailed description of preferred embodiments of the present invention that proceed with reference to the appending drawings:
Hereinafter, preferred embodiments for implementing the present invention will be described with reference to the appending drawings. In this regard, the embodiments described below do not tend to limit the invention as claimed in each of the claims described below. Further, it is not always true that all of combinations of the features explained in the embodiments are essential for elements of the present invention.
A basic structure of an electric cutting tool according to the present invention will first be described with reference to
The electric cutting tool 10 according to the present invention is configured so as to include: a surface plate 11 mounted on a processed material; a body portion 21 tiltably provided on this surface plate 11; and a circular saw blade 41 capable of rotating by means of driving power from a driver such as a motor 25 provided in the body portion 21.
The surface plate 11 is a member on which the body portion 21 is installed. The surface plate 11 is configured so as to have a substantially rectangular shape when viewed from the above (see
An opening portion 12 is formed in this surface plate 11. The opening portion 12 allows the circular saw blade 41 included in the body portion 21 to move up and down. An operator can specify a cutting position of a processed material by viewing the processed material from this opening portion 12. In this regard, although it is not shown in the drawings, a mark or the like, which becomes alignment for cutting, is formed in the vicinity of the opening portion 12 on an upper surface of the surface plate 11. Accurate processing can be made by carrying out the cutting processing while aligning this mark with an ink line drawn on a processed material.
Further, a safety cover 42 (to be described later) passes through the opening portion 12. The safety cover 42 is provided for a lower circumference of the circular saw blade 41. For that reason, the opening portion 12 having a shape based on shapes of the circular saw blade 41, the safety cover 42 and the like is adopted. In particular, swarf generated from a processed material by means of the rotating circular saw blade 41 is rolled up when cutting processing is carried out. However, since the opening portion 12 is formed so as to be narrowed to a minimum necessary opening range, it is possible to effectively prevent swarf from depositing on the surface plate 11.
The body portion 21 is installed above the surface plate 11 described above in a tiltable state in an up-and-down (vertical) direction (that is, a direction along a rotational direction of a circular saw blade 41) and a right-and-left (horizontal) direction (that is, a direction in which the circular saw blade 41 is to be tilted to the side surface). A connecting structure between the surface plate 11 and the body portion 21 for achieving such an action will be described. At a front side of the electric cutting tool 10, the body portion 21 is rotatably connected to the surface plate 11 via a pivot 22. The body portion 21 is configured so that a back side of the body portion 21 can be tilted to the vertical direction with respect to the surface plate 11 using this pivot 22 as the center of rotation. Therefore, the operator is allowed to tilt the back side of the body portion 21 to the vertical direction with respect to the surface plate 11, and to move the circular saw blade 41 to a direction along the rotational direction of the circular saw blade 41 by causing the circular saw blade 41 to protrude or retract from the opening portion 12 of the surface plate 11. The operator can thus carry out cutting processing by means of the circular saw blade 41. Further, it is possible to adjust a cutting depth (depth of cut) by adjusting an amount of protrusion of the circular saw blade 41.
In order to fix the body portion 21 described above to a desired tilt position, a link member 13 is installed at the upper surface in the back side direction of the surface plate 11 (see
On the other hand, as shown in
The body portion 21 includes: a housing 26 for receiving (or housing) the motor 25 that is a driving source; a cover portion 27 that covers an upper portion of the circular saw blade 41; and a handle 28 as a gripper (gripping section), which is formed on an upper portion of the housing 26 for operating the electric cutting tool 10.
A switch lever 28a for driving rotation of the circular saw blade 41 is provided in the handle 28. When the operator presses the switch lever 28a, the motor 25 is driven. Thus, the cutting processing can be implemented by transmitting rotary driving power to the circular saw blade 41.
Further, as shown in
Moreover, a lower half of the circular saw blade 41 is covered by the safety cover 42. The safety cover 42 is configured so as to be tilted and stored in the inside of the cover portion 27 that covers the circular saw blade 41 by being pressed by means of a processed material when the processed material is cut. This makes it possible to ensure safety for the operator while the cutting motion is not inhibited.
As shown in
A fan 25b is fixed at a front side of a motor shaft 25a included in the motor 25. The fan 25b is rotated when the motor 25 is driven, whereby cooled wind is introduced into the housing 26. Therefore, the motor 25 and the like that become a heat generating source are cooled suitably, and the electric cutting tool 10 can be operated suitably.
Further, both ends of the motor shaft 25a included in the motor 25 are supported by bearings 31, 32, respectively. A start gear 25c is formed at an end portion of the front side of the motor shaft 25a. On the other hand, a saw blade shaft 41a in which the circular saw blade 41 is installed via the plurality of gear groups is installed under the start gear 25c. The saw blade shaft 41a is supported to the inside of the housing 26 via bearings 33, 34. Such a configuration causes a substantially lower half of the circular saw blade 41 to protrude downward from a lower end of the housing 26 via the opening portion 12 of the surface plate 11. In this regard, an end gear 41b is fixed at a tip portion of the saw blade shaft 41a that enters the housing 26.
As shown in
In the electric cutting tool 10 according to the present invention having such a configuration, the rotary driving power of the motor 25 is transmitted from the start gear 25c of the motor shaft 25a to the end gear 41b via the first gear 35a and the second gear 35b, and is finally transmitted to the saw blade shaft 41a. As a result, the circular saw blade 41 is configured to be rotatively driven.
The electric cutting tool 10 according to the present invention has a basic configuration explained above. Moreover, the electric cutting tool 10 also has a significant configuration in which a cutting depth and/or an inclination angle of the circular saw blade 41 can be calculated with high accuracy and its calculation result can be displayed at a place arranged at a position viewable for the operator. Now, significant features that the electric cutting tool 10 according to the present invention has will be described using
The electric cutting tool 10 according to the present invention includes a movement amount measuring section 50 for measuring a movement amount (distance) of the body portion 21 with respect to the surface plate 11 in response to a tilting action. This movement amount measuring section 50 is configured as an incremental type of encoder that is a conventional technique. Namely, the movement amount measuring section 50 according to the present embodiment is configured by a magnetic scale 51 and a magnetic detecting head 52. The magnetic scale 51 is installed on the link member 13 included in the surface plate 11. The magnetic detecting head 52 is installed within the cover portion 27 included in the body portion 21.
The magnetic scale 51 is a member configured as a scale section including scale marks (measurements) arranged at predetermined intervals. More specifically, minute magnetic patterns are recorded in a magnet material, and are utilized as scale marks of a scale (or ruler). The magnetic scale 51 is attached onto the upper side of the link member 13 formed so as to extend along a tilt direction of the body portion 21.
On the other hand, the magnetic detecting head 52 is a member configured as a scale detecting section for detecting the scale marks included in the magnetic scale 51 configured as a scale section. More specifically, the magnetic detecting head 52 is one for measuring a movement amount (distance) of the body portion 21 with respect to the surface plate 11 in response to a tilting action by reading out scale marks of the magnetic scale 51 and converting a read-out result into an electrical signal.
In this regard, the magnetic detecting head 52 is swingably attached so as to have a shaft member 52a and move along the magnetic scale 51 attached onto the upper side of the link member 13. For example, when a state of the body portion 21 is shifted from a state where the body portion 21 is held up (or lifted) upward as shown in
On the other hand, a calculation and display section 60 is installed between the handle 28 as the gripper included in the body portion 21 and the cover portion 27 (see
In this regard, an installed position of the calculation and display section 60 is provided between the handle 28 and the cover portion 27 as shown in
In the present embodiment, when the body portion 21 is operated, the magnetic detecting head 52 sliding on the magnetic scale 51 measures a movement amount (distance) of the body portion 21 with respect to the surface plate 11 in response to a tilting action. Data obtained by the measurement are transmitted (or sent) from the magnetic detecting head 52 that is the scale detecting section to the calculating section 61. The calculating section 61 obtaining measured data on the movement amount (distance) of the body portion 21 converts the measured data into a cutting depth of the circular saw blade 41. On this conversion, the calculating section 61 reads out calculation conditions, in which a conversion expression based on a shape of the electric cutting tool 10 stored in the storage section 63, a diameter of the circular saw blade 41 and the like are set up in advance, from the storage section 63, and calculates the cutting depth and/or the inclination angle of the circular saw blade 41. A calculation result obtained by the calculating section 61 is transmitted to the display section 62, and is instantly displayed on the digital liquid crystal screen included in the display section 62.
In this regard, the display section 62 allows a desired display form to be selected from various display forms. For example, a display unit of the cutting depth can be converted into any of various units such as “inch” based on the Imperial system and “Cun (=3.03 centimeters)” based on the Japanese measuring system in addition to “millimeter (mm)” based on the SI system of unit, and a converted unit can be displayed. In such a conversion and display process, when the operator pushes a unit switching button (not shown in the drawings), a unit switching command by an electrical signal is transmitted from the display section 62 to the calculating section 61, and the calculating section 61 receiving this command again transmits a display command by a new unit to the display section 62. This makes it possible to achieve selection of the display form.
The movement amount measuring section according to the present embodiment can measure not only a movement amount of the body portion 21 in response to a tilting action in a vertical direction (that is, a direction along a rotational direction of the circular saw blade 41), but also a movement amount by a tilting action in a horizontal direction (that is, a direction in which the circular saw blade 41 is to be tilted to the side surface). For example, as shown in
In this regard, the movement amount measuring sections 50, 50′ described above are configured as the incremental type of encoder that is a known art. Although explanation of its principle of operation is omitted, it is noted that an operation to carry out zero point adjustment and the like are required for every measurement.
As described above, the suitable embodiment of the present invention has been explained, but a technical scope of the present invention is not limited to the scope described in the above embodiment. A variety of changes and modifications can be added to the above embodiment.
For example, although a tip saw has been used as the circular saw blade 41 according to the embodiment described above, the present invention can be applied to any form of circular saw blade such as a diamond plate and a cutter for digging a groove.
Further, for example, in the embodiment described above, as shown in
Further, for example, as shown in
Further, an arrangement position of the magnetic scale 51 and the magnetic detecting head 52 that construct the movement amount measuring section 50 is not limited to the embodiment described above. Any modified form can be adopted within a range capable of fulfilling the similar function. In the embodiment described above, as shown in
Further, although the case where each of the movement amount measuring sections 50, 50′, 50″ according to the present embodiment described above is configured as an incremental type of encoder has been illustrated, the movement amount measuring section of the present invention can be configured as a capacitive absolute encoder. By adopting an absolute encoder as the movement amount measuring section, it is not required to carry out zero point adjustment for every measurement. This makes it possible to improve handleability thereof dramatically.
Further, the scale section and the scale detecting section constructing the movement amount measuring section according to the present invention are not limited to the magnetic scales 51, 51′, 51″ and the magnetic detecting heads 52, 52′, 52″ as described above, respectively. For example,
Further, the storage section 63 included in the calculation and display section 60 according to the present embodiment as described above can be omitted. Namely, in the case where a configuration in which the calculation process is carried out using the calculating section 61 and the calculation result and the like are not stored is selected, it is possible to obtain a reduction effect of production costs by omitting the storage section 63.
Further, each of the movement amount measuring sections 50, 50′, 50″ according to the present embodiment described above is one that detects a moving distance of a member. However, values detected by the movement amount measuring section of the present invention are not limited to the moving distance data. For example, the movement amount measuring section of the present invention can be configured so as to detect a movement amount as inclination angle data.
More specifically, as the electric cutting tool 10′ shown in
In this regard, as shown in
Here, a concrete example of the case where the angle sensor 90 is provided at the portion of the pivot (22) will be described with reference to
In the electric cutting tool 10′ shown in
A flange portion 22a is formed in the vicinity of a shaft end of the pivot 22 at a left side. The angle sensor 90 and a casing for installing a display section (display section installing casing) 64 are installed at a portion of a further left shaft end of the flange portion 22a in this order toward the shaft end.
The flange portion 22a is a member formed integrally with the pivot 22. A dust-proof packing 22b made of an O-ring is installed at an outer circumference of the flange portion 22a. The dust-proof packing 22b is installed between the flange portion 22a and the display section installing casing 64. Therefore, it is possible to surely prevent refuse such as swarf and liquid from scattering or invading (or breaking) into the angle sensor 90 that is precision mechanical equipment. Installation of the dust-proof packing 22b allows a prevention effect of damage and a false operation of the angle sensor 90 to be obtained suitably.
The display section installing casing 64 becomes a state where the display section installing casing 64 can be tilted with respect to the pivot 22 integrally with the body portion 21 including the cover portion 27. Further, the calculation and display section 60 including the display section 62 is integrally installed on the display section installing casing 64. Moreover, a battery 65, which becomes a power source for the calculation and display section 60, is installed within the display section installing casing 64. This installation position of the battery 65 is a left side of the electric cutting tool 10′ and no impeditive member exists on its front surface. For that reason, the electric cutting tool 10′ has a configuration by which maintenance such as replacement of the battery 65 can be carried out very easily.
Further, although the battery 65 is installed at an installation portion of a lid member 64a that is opened and closed when the battery 65 is replaced, a dust-proof packing (not shown in the drawings) is installed between the lid member 64a and the display section installing casing 64. For that reason, a configuration is adopted in which it is possible to surely prevent refuse and liquid from invading into the inside of the display section installing casing 64 from a space between the lid member 64a and the display section installing casing 64.
The angle sensor 90 is installed at the position sandwiched between the flange portion 22a and the display section installing casing 64 described above. The angle sensor 90 included in the electric cutting tool 10′ is constructed from a first substrate 90a fixed to the display section installing casing 64 and a second substrate 90b fixed to the flange portion 22a. Since the first substrate 90a is fixed to the display section installing casing 64, the first substrate 90a carries out a rotary motion with a tilting action when the body portion 21 carries out the tilting action using the pivot 22 as the center of rotation. On the other hand, since the second substrate 90b is fixed to the flange portion 22a that is fixed and not rotated, the second substrate 90b always maintains a fixed state. Therefore, when a tilting action for the body portion 21 is carried out, the first substrate 90a carries out the rotary motion with respect to the fixed second substrate 90b. It is possible to grasp an amount of change of an angle of the tilting action for the body portion 21 by detecting an amount of change of the rotary motion. As a result, it is possible to measure a cutting depth of the circular saw blade 41 or the like.
In this regard, in the modified form example shown in
As described above, although the suitable modified form examples that the present invention can take have been explained, a further modified form can be adopted for the pivot 22 and the angle sensor 90. For example, the pivot 22 of the electric cutting tool 10′ shown in
Namely, as the forms of the members constructing the electric cutting tool according to the present invention, various kinds of modified forms can be adopted within a range capable of fulfilling the operations and effects of the present invention as described above.
Moreover, as shown in
In this regard, in the case where the circular saw blade 41 is tilted in the horizontal direction, as shown in
However, installation of both the movement amount measuring section (50′, 90 and the like) for measuring the inclination angle data and the movement amount measuring section (50 and the like) for measuring the moving distance data to the electric cutting tool is not a necessary requirement for the present invention. Any one of the movement amount measuring sections may be provided, or both of the movement amount measuring sections may be provided. Thus, any combination can be adopted. For example, in the case of the electric cutting tool in which only the movement amount measuring section for measuring moving distance data is installed, the cutting depth D2 of the circular saw blade 41 in the perpendicular direction to the processed material W cannot be grasped when the circular saw blade 41 is tilted in the horizontal direction. However, a cutting depth in an oblique direction can be grasped. Namely, in the electric cutting tool according to the present invention, it is preferable to select a configuration of the movement amount measuring section and the like described above in accordance with various specific conditions such as use application of the electric cutting tool and a production cost.
Further, the case where the electric cutting tool 10 according to the present invention described above is configured as a handheld radial arm saw has been illustrated. However, the present invention can be applied to any other type of electric cutting tool within a range capable of fulfilling the similar operation and effect to the embodiments described above and various modified forms.
For example, the present invention can also be applied to a desktop type sliding circular saw 110 as shown in
In this regard, by providing an adjusting screw 115 as a lower limit stopper and a stopper abutting section 116 between the tilt supporting section 112 and the cutting machine body 113 to the sliding circular saw 110 shown in
Moreover, as a method of adjusting a cutting depth of the desktop type sliding circular saw 110 shown in
It is apparent from the following claims that embodiments to which such changes and modifications are added can be included in a technical scope of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2009-208109 | Sep 2009 | JP | national |
| 2010-142507 | Jun 2010 | JP | national |
