The present invention relates to power operated tools or machinery for performing working operations on a workpiece. More particularly, the present invention relates to improvements to a bevel detent control on a power miter saw.
Saws and other apparatuses designed for cutting or performing other working operations on a workpiece typically require adjustment mechanisms for moving the saw blade or cutting tool into an angular relationship to the workpiece. Examples of such equipment include cross-cut compound miter saws which are adapted for allowing the user to selectively move the saw blade into any of a number of positions or modes for square cutting, miter cutting, bevel cutting, or compound miter cutting where a combination miter angle and bevel angle are cut. In addition, some operations, such as dado cutting or shaping operations, for example, require the use of saw blades or other cutting or working devices of different shapes or sizes to be substituted for one another in order to perform the desired operation on the workpiece, whether the workpiece is composed of wood, plastic, metal or other materials.
To allow for the adjustment of the miter and the bevel angle, the saw blade, cutter or other working device is angularly adjustable with respect to a horizontal base and a vertical fence against which the workpiece is positioned. The miter adjustment allows the saw blade, cutter or other working device to move angularly with respect to the vertical fence while maintaining perpendicularity with the horizontal base. The bevel adjustment allows the saw blade, cutter or other working device to move angularly with respect to the horizontal base while maintaining perpendicularity with the vertical fence.
Bevel angle adjustment may require a user to set a detent to one of several predetermined angles by releasing a bevel adjustment lock and lifting a detent out of notch in a detent plate that is representative of a predetermined position in a detent plate, rotating the saw about a bevel axis to another predetermined position in the detent plate and allowing the detent to snap into another notch in the detent plate representative of a desired bevel angle.
Bevel adjustment mechanisms need to be easily activated and adjustable to optimize cutting efficiency and convenience.
Once the saw blade, cutter or other working device has been adjusted to the desired position with respect to the horizontal base and the vertical fence, locking mechanisms for the miter and bevel adjustment must be activated in order to prohibit movement of the saw blade, cutter or other working device with respect to the base and fence while the cutting operation is performed. These locking mechanisms need to be easily activated, adjustable and quick acting in order to optimize the efficiency of the cutting apparatus and provide convenience to the operator of the apparatus.
It is also advantageous to provide bevel stop mechanisms so that operators can change and easily locate common bevel angles. These bevel stop mechanisms need to be easily engaged and disengaged, adjustable and quick acting in order to optimize the efficiency of the cutting apparatus and provide convenience to the operator of the apparatus.
In accordance with the present invention, an improved bevel adjustment device is employed in a power tool, such as a miter saw. In an exemplary embodiment, the miter saw includes a table on which a workpiece is placed, a miter saw unit supporting a saw blade and having a motor for rotatably driving the saw blade, and a housing pivotally supporting the miter saw unit related to the table in such a manner that the miter saw unit is at least laterally pivotable. Further, the miter saw includes a bevel mechanism for selectively determining the angular position of the miter saw unit at any of a plurality of pivoted positions including a vertical position where the saw blade is positioned substantially vertically relative to the table, and leftward and rightward pivoted positions where the blade is inclined laterally leftwardly and laterally rightwardly from the vertical position.
The bevel adjustment device includes a switch mountable on the saw, a controller, and a motor that drives a mechanism to lock/unlock the saw from a current position to allow a user to rotate a saw about a bevel axis. The switch may also activate release of the detent from a lifted position to allow the bevel angle to be set to a desired position. The switch may be mounted, for example, on an operating handle of the saw in a position easily accessible by the user. The output of the switch may be connected to a controller used to control operation of the motor to activate actuators that move the detent.
Other advantages and objects of the present invention will become apparent to those skilled in the art from the subsequent detailed description, appended claims and drawings.
The present invention will become more fully understood from the detailed description given below and the accompanying drawings, which are given for purposes of illustration only, and thus do not limit the invention. In the drawings which illustrate the best mode presently contemplated for carrying out the present invention:
Referring now to the drawings in which like reference numerals designate like or corresponding parts throughout the several views, there is shown in
Referring primarily to
The housing assembly 16 is secured to table assembly 14 such that it can be pivoted with respect to table assembly 14 to provide adjustment for bevel cutting. As can be appreciated by one skilled in the art, the adjustments for mitering and bevelling can be separate. The pivoting of housing assembly 16 changes the angle of saw blade 18 relative to table assembly 14 but maintains the miter angle of saw blade 18 with respect fence assembly 26. A locking mechanism contained within bevel drive motor housing 56, can be activated/deactivated to lock/unlock housing assembly 16 to table assembly 14 at a desired bevel angle.
Referring to
Referring to
Locking mechanism 30 includes a motor 58, a controller 59, a rod 54, a cam 65 having a plurality of ramps 67 on a surface 66 and cam 52. Once support housing 32 is slidingly and pivotably received on shaft 40, cam 52 is slidingly positioned on shaft 40 adjacent support housing 32. Cam 52 includes a D-shaped through bore 60 which mates with a corresponding D-shaped portion 62 of shaft 40 such that cam 52 is allowed to move axially along portion 62 of shaft 40 but rotation of cam 52 with respect to shaft 40 is prohibited. Cam 52 further includes an angular camming surface 64 having a plurality of ramps 53 which are located on the radial surface of cam 52 which is opposite to support housing 32. Camming surface 64 is designed to mate with cam 65 as will be described later herein.
As shown in
In an example embodiment, a four-position toggle switch 25 (
In normal operation, the switch 25 is in home position 25a and the bevel angle of the saw is locked. To change the saw bevel angle, the switch is moved to position 25b and motor 58 rotates rod 54 to a position where angular camming surface 64 and angular camming surface 66 are in full contact with each other as shown in
The exemplary miter saw 10 may also incorporate additional features within housing assembly 16, including a detent system 70. Referring to
Table assembly 14 includes at least one detent. For example, as shown in
In an example embodiment, to change the bevel angle of the saw 10 using the detent system 70, a user pushes the switch 25 to the second of the second momentary positions 25d sending a signal to the controller 59 to unlock the bevel locking mechanism 30 and to move the stop rod 84 against the spring 82 to move the stop rod out one of the detents 80. For example, when the bevel angle needs to be changed, the switch 25 activates motor 58 through controller 59 to rotate the rod 54 and the cam 65 to release housing 32 from table assembly 14 and the motor 58 withdraws stop rod 84 from within table assembly 14 to a position at which stop rod 84 is not in a detent 80 and the housing 32 is pivoted on shaft 40 so that the bevel angle may be changed to a desired angle.
The user may then move the saw 10 so that the bevel angle is near or at a detent 80 and release the switch 25 to a first of the second momentary positions 25c to release the rod 84 into a detent 80 in the table assembly 14. The user may also release the switch 25 to allow the rod 84 to engage the table assembly at a point where there is no detent 80, then move the saw 10 such that the stop rod 84 would snap into a detent 80 in the table assembly 14. The user may then allow the switch 25 to return to the “home” position 25a to lock the housing 32 in place. In other words, the two momentary positions 25c, 25d to the left control the detent function. With the switch 25 all the way to the left and at a second momentary position 25d the detent would be out of play. With the switch 25 in the first momentary position 25c to the left the detent function is in play and the user may move the saw 10 and allow the stop rod 84 or rod 84 to snap into a detent 80 in the table assembly 14. On the other hand, if the user wanted to set the bevel angle to an angle that is not represented by a notch or detent in the detent plate 80, the user may push the switch 25 to the right to position 25b to cause both the bevel lock mechanism 30 to be unlocked and the rod 84 to be moved out of position. The user would then set the saw 10 to the desired bevel angle and release the switch 25. When the switch has returned to the “home” position 25a, the bevel lock mechanism 30 is locked and then, after a short delay, the rod 84 is released.
As would be apparent to one of ordinary skill in the art, the switch 25 having two positions 25c, 25d to the left may be replaced with a single switch position if another means is used to lock the bevel after the detent is in position. For example, a sensor (not shown) may be used to detect position of the detent and only lock the bevel after the detent is in position, or a time delay device may be used to lock the bevel after a predetermined time upon release of the detent.
In an example embodiment, the bevel angle of the saw 10 may be changed using a detent latch 82 (
In an example embodiment, as shown in
The user may then move the saw 10 so that the bevel angle is near or at a detent 80 and release the switch 25 to a first of the second momentary positions 25c, to release the rod 84 into a detent 80 in the table assembly 14. The user may also release the switch 25 to allow the rod 84 to engage the table assembly at a point where there is no detent 80, then move the saw 11 such that the stop rod 84 would snap into a detent 80 in the table assembly 14. The user may then allow the switch 25 to return to the “home” position 25a to lock the housing 32 in place. In other words, the two momentary positions 25c, 25d to the left control the detent function with the switch 25 all the way to the left and at a second momentary position 25d the detent would be out of play. With the switch 25 in the first momentary position 25c to the left the detent function is in play and the user may move the saw 10 and allow the stop rod 84 or rod 84 to snap into a detent 80 in the table assembly 14. On the other hand, if the user wanted to set the bevel angle to an angle that is not represented by a notch or detent in the detent plate 80, the user may push the switch 25 to the right to position 25b to cause both the bevel lock mechanism 30 to be unlocked and the rod 84 to be moved out of position. The user would then set the saw 10 to the desired bevel angle and release the switch 25. When the switch has returned to the “home” position 25a, the bevel lock mechanism 30 is locked and then, after a short delay, the rod 84 is released.
As would be apparent to one of ordinary skill in the art, the switch 25 having two positions 25c, 25d to the left may be replaced with a single switch position if another means is used to lock the bevel after the detent is in position. For example, a sensor (not shown) may be used to detect position of the detent and only lock the bevel after the detent is in position, or a time delay device may be used to lock the bevel after a predetermined time upon release of the detent.
Another switch embodiment would be to use 2 separate buttons. A first button is used if the user desired to set the saw to a preset detent. And a second button is used if the user desired to set the saw at a bevel angle between the detents.
In an example embodiment, as shown in
If the user desires to set the bevel angle using a bevel degree scale (e.g., a bevel angle not represented by a preset notch in the detent plate), the switch 25 is pressed twice and then held in place. When the bevel angle is at the desired location, the switch 25 is released causing the control circuit 59 to actuate the bevel locking mechanism 30, and then after a delay release the stop rod 84 or bevel detent thereby allowing the bevel angle to be set at any position without regard to the preset bevelled angles represented by notches in the bevel plate. In an embodiment the electric motor 58b may drive the stop rod 84 to lock the bevel angle, and the electric motor 58a may drive a rod 54 to lock the miter saw 10 in a bevelled position. The motor 58 may drive the threaded rod 54 through a gear reduction to generate sufficient torque and is actuated by a switch 25 mounted in the operating handle 24 of the miter saw 10. In an example embodiment the motor driven stop rod 84 may be used to lift or release detent latch 82 out of engagement with the detent plate 80. For example, the stop rod 84 may be connected at a first end to a drive motor 58 and a second end to the detent latch 82. The detent latch 82 may comprise spring steel that, when released, springs against the detent plate 80 at a desired location (
The above detailed description describes different embodiments of the present invention. For example, persons skilled in the art will recognize that a motor/screw jack assembly can be replaced by a motor/actuator assembly to activate the bevel lock mechanism and the detent control system.
This application claims the benefit of U.S. Provisional Application No. 61/129,031 filed on May 30, 2008. The disclosure of the above application is incorporated herein by reference in its entirety.
Number | Date | Country | |
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61129031 | May 2008 | US |