WO2019231703A1

WO2019231703A1 - Band saw with a wheel supporting two blades mounted back to back

Info

Publication number: WO2019231703A1
Application number: PCT/US2019/032651
Authority: WO
Inventors: John W. WIGHTMAN
Original assignee: Edge Manufacturing, Inc.
Priority date: 2018-05-30
Filing date: 2019-05-16
Publication date: 2019-12-05

Abstract

A band saw (1) capable of cutting in both directions includes two wheels (13A, 13B), each carrying two blades (21A, 21B) arranged back-to-back. The wheels (13A, 13B) have a central flange (17) separating the blades (21A, 21B) and acting as a stop for the blades.

Description

BAND SAW WITH A WHEEL SUPPORTING TWO BLADES MOUNTED BACK TO BACK

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patent Application No. 62/678,096, filed May 30, 2018, the disclosure of which is hereby incorporated by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

Not Applicable.

FIELD OF INVENTION

The present invention relates to band saws.

BACKGROUND OF THE INVENTION

A band saw has at least two wheels in a plane holding one band saw blade.

If the purpose of the saw is to make repeated cuts in the same product, such as meat in a packing house, the operator must guide the product through the band completing the cut, then bring the product back around to the front of the saw and repeat the motion. Any attempt to automate this process runs into the same obstacle. Much time and motion is wasted in this process.

To be more efficient and utilize the return motion to its optimum, the saw needs to be able to cut the product with the forward stroke and the backward stroke. To accomplish this process, the saw will require saw wheels able to accommodate blades that allow cutting in both directions. One way to accomplish this mission is to have a single band saw blade with teeth on both edges of the blade. This allows the saw to cut in both forward and backward directions. A blade of this type is expensive and difficult to produce.

Johnston, Sr., U.S. Patent No. 6,722,248, solves this for cutting lumber from a log by essentially having two band saws on a common carrier. A saw of this type is expensive because two band saws are required to achieve the result.

Bergvall, et al., U.S. Patent No. 6,532,850, utilizes both two band saws and blades with teeth on both edges.

All patents mentioned herein are hereby incorporated by reference. BRIEF SUMMARY OF THE INVENTION

Another way to resolve this problem is the subject of this invention. In accordance with this invention, a unique band saw wheel is provided which will accommodate two blades arranged back-to-back.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a somewhat diagrammatic perspective view of a dual cutting direction band saw in accordance with an embodiment of the present invention.

FIG. 2 is a fragmentary view in perspective from below of the band saw of

FIG. 1 .

FIG. 3 is a side plan view of a band saw wheel in accordance with an embodiment of the invention.

FIG. 4 is a detail of a portion of the wheel of FIG. 3, taken along circle 4-4 of FIG. 3.

FIG. 5 is a view in perspective of the wheel of FIG. 3.

FIG. 6 is a detail of the blades of the band saw of FIGS. 1 -2, taken along circle 6-6 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The following detailed description illustrates the invention by way of example and not by way of limitation. The description clearly enables one skilled in the art to make and use the invention, and describes several embodiments, adaptations, variations, alternatives, and uses of the invention, including what is presently believed to be the best mode of carrying out the invention.

As shown in FIGS. 1 and 2, a typical band saw 1 includes a frame 3 supporting a drive shaft 5 and a parallel passive shaft 7. The drive shaft 5 is driven by a motor 9. Spaced-apart wheels 13 are mounted on the shafts 5 and 7. A hub 1 1 of a drive wheel 13A is mounted to the drive shaft 5 for rotation with it, and the hub 1 1 of an identical free wheel 13B is rotatably mounted on the passive shaft 7. Typically, the passive shaft 7 is moveable up U and down D to allow for tensioning the band saw blade.

This embodiment of the present invention differs from prior band saws in having wheels 13 that will carry two blades mounted back-to-back. The Figures illustrate one illustrative embodiment of band saw wheels 13 that permit forward F and reverse R cutting on a band saw. This band saw wheel 13 contains several design features making forward and back cutting easy. The wheels 13 may utilize standard saw blades. One unique feature is a wheel 13 having a rim 15 with a flange 17 that is located in the center of the rim 15 on the wheel 13. This flange 17 is preferably continuous around the entire diameter of the wheel 13. This allows the wheel 13 to accommodate two band saw blades 21 , shown in the drawings as 21 A and 21 B. The teeth 19 of both blades 21 are facing away from the center flange 17, with the teeth 19 of both facing in the same cutting direction, usually downward, through the cutting plane or table, 25. It will be seen that if the blades 21 are identical, one of them must be turned inside out. The purpose of the flange 17 is to provide the band saw blades 21 a back edge stopping point preventing the two blades 21 from touching each other and to center the blades 21 on the rim 15 of the wheel 13. Both the top wheel 13B and the bottom wheel 13A share this design.

At times a band saw blade 21 may tend to track away from the flange and track toward the edge of the wheel. If the blade 21 goes far enough, it can track off of the band saw wheel 13. To help prevent this, the surface of the rim 15 of the wheel 13 can be made such that the outer edge of both sides of the wheel 13, (in other words the tooth edge of the wheel) is of slightly larger diameter than the diameter of the wheel 13 at the base of the flange. There will be a slight relief angle Q on the rim 15 of both the front and back blade 21 riding surfaces causing the blades to stay centered on the saw wheel rim 15. This will put more tension on the tooth edge of the blade 21 preventing it from traveling forward off of the wheel 13. The amount of relief angle Q may vary based on the size or the type of material of the band saw blade, the amount of camber in the band saw blade, or the diameter of the wheel 13 as determined by those skilled in the art.

The top wheel 13B and the bottom wheel 13A will be similar, but may not be identical. For example the wheel diameter or the relief angle Q may be different.

Most band saws have some mechanism for supporting or guiding the back of the blade while cutting. The band saw using these wheels may need the same support or guide 23. The guide 23 must be made of a wear resistant material. The guide 23 may take on several shapes including round, square, rectangular, rotatable, etc. For illustration a square guide 23 is shown in FIG. 2. In this illustration the guide 23 is mounted under a table 25 that carries the material to be sawed. This is also purely illustrative. The band saw may have an upper guide and lower guide or just one or the other. The band saw may have the guide mounted to the table or to the frame. For certain automation applications the band saw may not even have a table. The guide is there to prevent the blade from being pushed excessively in the cutting plane towards the other blade. This will also allow higher cutting forces without damaging the blades 21 or wheels 13. The blade may also require side guides either as part of the guide 23 or a separate guide similar to that which is available on commercial band saws.

Numerous variations, within the scope of the appended claims, will occur to those skilled in the art in light of the foregoing disclosure. Merely by way of example, the description above is for a wheel 13 made of one piece, but the wheel may be fabricated with various methods to achieve the same result. For example the wheel assembly could be made of two narrower wheels both with the same angle and a disk between them to act as the flange 17. A blade-engaging coating may be provided on the rim of the wheel. Additional wheels may be provided in many situations. These variations are merely illustrative.

Claims

1 . A band saw comprising at least two spaced-apart wheels rotatable in a common plane about parallel axes and two band saw blades mounted on the wheels and extending between the wheels, the blades being mounted back-to- back, the blades having cutting teeth facing in the same cutting direction.

2. The band saw of claim 1 wherein each wheel comprises at least one spacer between the two blades.

3. The band saw of claim 2 wherein the at least one spacer comprises a continuous flange extending midway between axial edges of the wheel.

4. The band saw of any of claims 1 -3 wherein blade-bearing surfaces of each wheel have a larger radius at both axial edges than at some positions spaced inward from the axial edges.

5. The band saw of claim 3 wherein an outer edge of both sides of the wheel is of larger diameter than the diameter of the wheel at the base of the flange.

6. The band saw of claim 1 further comprising a guide structure positioned between the wheels, the guide structure being sized and positioned to limit movement of both blades in a cutting plane.

7. The band saw of claim 6 wherein the band saw comprises a table supporting a material being cut.

8. The band saw of claim 6 or 7 wherein the guide structure is mounted to the table.

9. A band saw comprising at least two spaced-apart wheels rotatable in a common plane about parallel axes, each wheel comprising peripheral rim, the rim having a central flange and blade-engaging surfaces, the blade-engaging surfaces having a larger diameter axially away from the flange than at the flange, axial edges of the peripheral rim having no flange.

10. The band saw of claim 9 wherein the flange is continuous.