Patent Application
20230398615
A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the reproduction of the patent document or the patent disclosure, as it appears in the U.S. Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.
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The present disclosure relates generally to band saws and tensioning the blades in such bandsaws.
More particularly, the present disclosure relates to using a device to adjust the tensioning of a blade in a band saw. In some conventional devices manual adjustment devices are provided, where the blade guide wheels can be mounted to a movable chassis that can be moved using a manual screw device, such as the device taught in U.S. Pat. No. 7,594,462. Prior art devices can include a load cell coupled to the movable chassis and operable to effectively measure the force applied between the guide wheel via the movable chassis and a frame of the band saw, which is representative of the tension in the blade which applies a force onto the guide wheel.
Prior art systems utilized a manual screw adjustment to move the position of the guide wheel and thus adjust the tension in the band saw. Such devices require the band saw to be stopped and in some cases housing components to be removed to access the blade adjustment screw/knob, which is cumbersome. The prior art devices included a load cell for measuring the tension in the blade and a display for showing the tension, but if the tension slacked over time the device would have to be stopped to perform the adjustment mechanism. Manually adjusting the tension in the blade also requires a substantial amount of force, which could be difficult to provide with a manual force applied to the adjustment screw.
What is needed then are improvements to band saws and blade tension adjustment mechanism provided therein.
This Brief Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
One aspect of the present invention is a band saw including a frame, a guide wheel, a blade disposed around the guide wheel, and a guide wheel chassis movably disposed on the frame, the guide wheel rotatably connected to the guide wheel chassis. The band saw can include a blade tension adjustment assembly including a tensioning motor, wherein operation of the tensioning motor produces movement of the guide wheel chassis and the guide wheel relative to the frame to adjust the tension of the blade. A tension gauge can be engaged with the guide wheel chassis and operable to determine a tension in the blade. A controller can be communicated with the tensioning motor and the tension gauge, the controller operable to receive tension data representative of the tension in the blade from the tension gauge and control operation of the tensioning motor based on the tension data to control the tension of the blade. In some embodiments, the controller can be operable to adjust the tension of the blade during operation of the band saw while the blade is spinning.
In some embodiments, the band saw can further include a display communicated with the controller, the display including a user interface for receiving tension input commands from a user, the controller operable to control the tensioning motor based on the received tension input commands from the user. In some embodiments, the user interface can allow a user to create saw blade size and blade tension presets or profiles for easy access when changing blades for conventional or often used saw blades.
While any suitable blade tensioning and tension gauge structures can be utilized in the band saw of the present disclosure with a tensioning motor for driving movement of the guide wheel chassis, in some embodiments the frame can include a frame guide block rigidly mounted to the frame, the tensioning motor include a drive shaft threadingly engaged with the frame guide block. The guide wheel chassis can further include a pair of guide rods moveably extending through the frame guide block, the guide rods each having a first end and second end. A motor platform can be positioned on a first end of the guide rods, the tensioning motor mounted to the motor platform. A retention plate can be positioned on a second end of the guide rods. A wheel guide structure can be slidably disposed on the guide rods between the frame guide structure and the retention plate, the guide wheel rotatably connected to the wheel guide structure. A spring can be positioned between the retention plate and the wheel guide structure, the tension gauge positioned between the spring and either the retention plate or the wheel guide structure such that the spring applies a force on the tension gauge substantially equal to the tension in the blade.
The use of a motorized tensioning assembly can allow for more efficient and automated tensioning of the blade, because the tensioning can be done without having to manually turn knobs and open up saw housings etc. The tensioning can also be done while the saw is operational as manual adjustment has been removed. Thus, the band saw of the present disclosure can help reduce down time for the saw due to adjusting the tension in and/or changing blades.
Numerous other objects, advantages and features of the present disclosure will be readily apparent to those of skill in the art upon a review of the following drawings and description of a preferred embodiment.
While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts that are embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention and do not delimit the scope of the invention. Those of ordinary skill in the art will recognize numerous equivalents to the specific apparatus and methods described herein. Such equivalents are considered to be within the scope of this invention and are covered by the claims.
In the drawings, not all reference numbers are included in each drawing, for the sake of clarity. In addition, positional terms such as “upper,” “lower,” “side,” “top,” “bottom,” etc. refer to the apparatus when in the orientation shown in the drawing. A person of skill in the art will recognize that the apparatus can assume different orientations when in use.
An embodiment of a band saw 10 of the present disclosure is shown in
One aspect of the present invention is a band saw with an improved blade tensioning and gauge system. The band saw 10 can include a frame 12, a guide wheel 16, a blade 14 disposed around the guide wheel 16, and a guide wheel chassis 18 movably disposed on the frame 12, the guide wheel 16 rotatably connected to the guide wheel chassis 18. The band saw 10 can include a blade tension adjustment assembly 20 including a tensioning motor 22, in some embodiments including a threaded drive shaft 24, wherein operation of the tensioning motor 22 produces movement of the guide wheel chassis 18 and thus the guide wheel 16 relative to the frame 12 in order to adjust the tension of the blade 14. A tension gauge 26 can be oriented to determine a tension in the blade 14. In some embodiments, the tension gauge 26 can be engaged within the guide wheel chassis 18 of the band saw 10 and operable to determine a tension in the blade 14. A controller 28 can be communicated with the electric tensioning motor 22 and the tension gauge 26, the controller 28 operable to receive tension data from the tension gauge 26 and control operation of the tensioning motor 22 based on the tension data to control the tension of the blade 14. The tension gauge 26 can be any suitable device for measuring an equivalent force substantially equal to the tension in the blade 14, or for indirectly measuring the tension in the blade, as discussed in more detail herein. For instance, in some embodiments, the tension gauge can include, but is not limited to, a load cell, strain gauge, flex sensor, rotary gauge, linear gauge, etc.
In other embodiments, a servo motor can be used for the tensioning motor 22 of the band saw 10. As tension in the blade 14 increases, the load on the servo motor 22 can increase to drive the blade tension adjustment assembly 20 under the increased tension. Thus, the servo tensioning motor 22 can be used to monitor the tension in the blade 14 as opposed to a separate load cell or other tension gauge structure, such that the tensioning motor 22 can also act as the tension gauge 26. The controller 28 can be programmed to monitor load outputs from the tensioning motor 22, associate or correlate such load outputs with an equivalent tension in the blade 14, and adjust the positioning of the guide wheel 16 accordingly utilizing the tensioning motor 22 as the tension gauge 26.
In some embodiments, the controller 28 can be operable to adjust the tension of the blade 14 during operation of the band saw 10 while the blade 14 is spinning. For instance, as the band saw 10 operates the blade 14 can heat up causing the blade 14 to expand, which can decrease the tension in the blade 14. The blade 14 can also stretch over time, or the guide wheels 16 can be subject to wear or deformation, again decreasing the tension in the blade 14. The controller 28 can continuously monitor for these tension changes via the tension gauge 26 and control the motor 22 to adjust the tension as needed. As such, operation of the band saw 10 does not need to be stopped to adjust the tension in the blade 14, which provides a significant improvement in the performance and adjustment capabilities of the band saw compared to systems with manual adjustment mechanisms. In some embodiments, the controller 28 can be programmed to not decrease the tension in the blade 14 when an increase in the tension is observed for a short period of time, for instance in cutting curves and the blade is potentially bent slightly during use but returns to its normal shape post cut.
In some embodiments, the tension gauge 26 can be used to detect an emergency condition, such as a de-tensioning or breaking of the blade 14. The controller 28 can monitor for the tension decreasing below a predetermined emergency threshold during normal operation of the band saw 10 and shut down the band saw automatically if the emergency condition is detected. In such scenarios, the controller 28 immediately shutting off the band saw 10 can help reduce any injury to a user of the machine due to a broken or de-tensioned blade 14.
In some embodiments, the band saw 10 can include a manual tension quick release handle including a cam, which can be moved from an untensioned position to a tensioned position. When the quick release handle is moved from the untensioned position to the tensioned position, the cam passes an inflexion point wherein the tension in the blade 14 can retain the quick release handle in the tensioned position. The band saw 10 can further include a limit switch that is only closed when the manual tension quick release handle is in the full tensioned position. The quick release handle can be weighted and positioned such that if the blade breaks or runs off the wheel, such that blade tension on the cam of the quick release handle is removed, the weight of the handle will overcome the cam that raises the wheel to tension the blade, the handle will fall, and the limit switch will open up, stopping the motor. This mechanism can provide an additional safety feature to stop the motor of the band saw 10 if the blade 14 loses tension.
In some embodiments, the band saw 10 can further include a display 30 communicated with the controller 28, the display 30 including a user interface 32 for receiving tension input commands from a user, the controller 28 operable to control the tensioning motor 22 based on the received tension input commands from the user. In some embodiments, the user interface 32 can allow a user to create saw blade size and blade tension presets or profiles, as shown in
Referring again to
Because the wheel guide structure 44 is slidably disposed on guide rods 36, the force applied by the spring 42 on the wheel guide structure 44 (via the tension gauge 26) as the motor 22 moves the retention plate 40 is the force that moves the wheel guide structure 34 in an upward direction. The blade 14 will resist such a force such that the spring 42 can apply a force on the tension gauge 26 substantially equal to the tension force from the blade 14 on the guide wheel 16. As such, the force applied by the spring 42 on the tension gauge 26 can be used to measure the tension of the blade 14.
In some embodiments, the tension gauge 26 can include a load cell operable to measure a direct force applied on the load cell 26 via the spring 42. In other embodiments, the guide wheel chassis 44 can be threadingly coupled to the drive shaft 24 of the motor 22. In such embodiments, the drive shaft 24 can be directly engaged with the load cell 26 such that as the blade 14 is tensioned, the drive shaft 24 can produce a force on the load cell 26 equal to the tension force in the blade 14.
In still other embodiments, the tension gauge 26 can indirectly measure the tension in the blade 14, for instance by measuring the change in dimension or deflection in one or more components of the band saw 10 or blade tensioning assembly and correlate or calibrate that measurement with a tension in the blade 14. For instance, as shown in
In some embodiments, as shown in
In other embodiments, as shown in
In still other embodiments, a pneumatic pressure gauge can be used which can be oriented to be compressed as the tension in the blade 14 increases. The pressure in the gauge can be calibrated to correlate to varying tensions in the blade 14. While several types of suitable tension gauges 26 have been described herein, any suitable tension gauge 26 for determining the tension in the blade 14 either directly or indirectly can be utilized.
In still other embodiments, as shown in
In still other embodiments, as shown in
In some embodiments, as shown in
As the tensioning motor 22 is operated, the threaded drive shaft 24 will engage the frame guide block 34. Because the frame guide block 34 is fixedly connected to the frame 12, and the tensioning motor 22 is prevented from rotating via motor platform 38 (and guide rods 36 extending through the frame guide block 34), the rotation of the drive shaft 24 will cause the motor 22 and thus the guide rods 36 and retention plate 40 to move with the motor 22. In tensioning the blade 14, the motor 22 can move in an upward direction relative to the frame guide block 34, thereby moving the guide rods 36 and the retention platform in an upward direction. This upward movement further compresses the spring 42 which forces the guide wheel 16 upward which such that the tension in the blade 42 increases to balance this increased force from the spring 42. Similarly, to reduce the tension of the blade 14, the motor 22 can be operated in the reverse direction to lower the motor 22, guide rods 36, and retention plate 44, in order to release the compression of the spring 42, lower the guide wheel 16, and thus reduce the tension in the blade 14.
In some embodiments, guidepost 46 can extend between the tension gauge 26 and the retention plate 40 and through the spring 42 such that the guidepost 46 can maintain the spring 42 in a desired location within the guide wheel chassis 18. In some embodiments the guidepost 46 can extend from the retention plate 40 and through the spring 42. In other embodiments, the guidepost 46 can extend from the tension gauge 26 or the wheel guide structure 44.
The figures in this application show an embodiment wherein the motor 22 is above the wheel guide structure 44 and the frame guide block 34 such that the motor 22 can move upward and away from the frame guide block 34 to pull the retention plate 44 and the guide wheel 16 in an upward direction. In some embodiments the motor 22 can be positioned below the wheel guide structure 44 on the lower retention plate 40 and threadingly engaged with the frame guide block 34, such that the motor 22 can move upward with the retention plate 40 in operation toward the frame guide block 34 to move the retention plate 40 and the guide wheel 16 upward to tension the blade.
In still other embodiments, similar to the structure shown in U.S. Pat. No. 7,594,462, the motor drive shaft 24 can extend through the wheel guide structure 44 and/or the guide wheel chassis 18 and be threadingly engaged with a threaded nut or the tension gauge 26 directly, such nut or tension gauge being restricted from rotation by either the wheel guide structure 44 or some other structure of the guide wheel chassis 18 and the spring 42 can be positioned between the wheel guide structure 44 and the threaded nut or tension gauge 26. As the motor is operated, the threaded nut or the tension gauge 26 could move along the drive shaft 24, thus compressing or releasing compression in the spring 42 to change the force applied on the wheel guide structure 44 by the spring 42, and thus the tension in the blade 14.
A method of changing a blade and monitoring the tension of the blade during operation can be seen in
In some embodiments, the controller 28 can be programmed to recognize when the saw remains inactive for a user configurable or preset period, and once that idle state is reached the motor will partially release the tension to prevent flat spots or deformation of the guide wheel and/or blade stretch. If the user presses the START button or otherwise powers up the band saw 10 during the partial tension state, the tensioning motor will apply full tension before allowing the primary drive motor to start.
Thus, although there have been described particular embodiments of the present invention of a new and useful BLADE TENSIONING SYSTEM AND GAUGE FOR A BAND SAW, it is not intended that such references be construed as limitations upon the scope of this invention.
This application claims the benefit of U.S. Provisional Application Ser. No. 63/351,649 filed on Jun. 13, 2022 and titled “Blade Tensioning System And Gauge For A Band Saw,” which is incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63351649 | Jun 2022 | US |
