Band saw with rotating saw blade

Abstract

Band saw (10) including: a frame (12); a first wheel (16) and a second wheel (18) which are supported by the frame (12); a band saw blade (14) which is looped around the first wheel (16) and the second wheel (18) and is held under tension between the first wheel (16) and the second wheel (18); a first blade guide arrangement (20) and a second blade guide arrangement (22) which guide the band saw blade (14) through a cutting zone (34), wherein the first blade guide arrangement (20) is arranged on a first side and the second blade guide arrangement (22) is arranged on a second side of the cutting zone (34); and a lever arm (52) that is coupled to both the first blade guide assembly (20) and the second blade guide assembly (22), wherein the lever arm (52) is designed to be moved manually by an operator of the band saw, wherein the movement of the lever arm (52) moves the first blade guide assembly (20) and the second blade guide assembly (22) simultaneously between the first angular position and the second angular position, wherein the lever arm (52) is designed such that it is decoupled from the first blade guide arrangement (20) and the second blade guide arrangement (22) and is moved to a rest position, wherein the first wheel (16) and the second wheel (18) define a tangential wheel contact plane that extends through the cutting zone (34), wherein the first blade guide arrangement (20) and the second blade guide arrangement (22) are each mounted for a pivoting movement about a rotational axis between a first angular position and a second angular position, wherein the first blade guide arrangement (20) and the second blade guide arrangement (22) are each selectively lockable in the first angular position and the second angular position, wherein in the first angular position the first and the second blade guide arrangement (20, 22) hold the band saw blade (14) at a first angle to the wheel contact plane and wherein in the second angular position the first and the second blade guide arrangement (20, 22) hold the band saw blade (14) at a second angle to the wheel contact plane, the second angle being different from the first angle.

Description

AREA OF TECHNOLOGY

[0001] The disclosure relates generally to band saws and in particular to guide arrangements and clamping arrangements for band saws. STATE OF THE ART

[0002] Unless otherwise stated herein, the materials described in this section are not prior art for the claims of this application and are not declared prior art by their inclusion in this section. Band saws of this type are disclosed, for example, in publications DE 10 2007 005 581 A1, GB 2 389 334 A, US 5,410,934 A, US 4,926,731 A, US 4,036,269 A and DE 20 2009 011 781 U1.

[0003] Different types of band saws are suited to different tasks. This is partly due to the angle of the saw blade relative to the tangential wheel contact plane. The blade angle controls the direction of movement of a workpiece relative to the band saw frame. Existing vertical band saws, designed for rip and contour cutting, have a blade angle of 0° to the tangential wheel contact plane. Portable handheld band saws, designed for crosscutting pipe and bar stock, have a blade angle of 45° to the tangential wheel contact plane. Horizontal band saws either have a blade angle of 0° for sawmill rip cuts or a blade angle of up to 90° and a pivot pin for crosscuts.

[0004] On the one hand, the capacity for performing crosscuts on a vertical band saw with a blade angle of 0° is very limited. On the other hand, the capacity for performing rip cuts on a band saw with a blade angle of 45° or 90° is also very limited. There is a need for a tool with a variable blade angle that can meet the high capacity requirements for both rip and crosscut cutting and that can be easily and efficiently switched between blade angles, taking into account changes in blade tension due to the twisting of the saw blade. According to a first aspect of the invention, a band saw according to claim 1 is provided. According to a second aspect of the invention, a band saw according to claim 8 is provided. According to a third aspect of the invention, a band saw according to claim 12 is provided.Further aspects of the invention are the subject of the dependent claims, the drawings and the following description of exemplary embodiments. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a schematic side view of a band saw according to the present disclosure. Fig. Figure 2 is a schematic front view of the band saw from Fig. 1. Fig. Figure 3 is a schematic representation of the blade guide arrangements of the band saw of Fig. 1 in a first angular position. Fig. Figure 4 is a schematic representation of the blade guide arrangements of the band saw of Fig. 1 in a second angular position. Fig. Figure 5 is a schematic representation of the blade guide arrangements of the band saw of Fig. 1 in a third angular position. DETAILED DESCRIPTION

[0005] For a better understanding of the principles of the disclosure, reference is now made to the embodiments illustrated in the drawings and set forth in the following written description. It is understood that this is not intended to limit the scope of the disclosure. It is also understood that the present disclosure includes any modifications and variations of the illustrated embodiments and furthermore encompasses applications of the principles of the disclosure that would normally be obvious to a person with average expertise in the relevant field.

[0006] The disclosure relates to a band saw with rotating blade guide assemblies that allow for a variety of blade angles relative to the contact plane of the drive wheel. A blade angle of 0° permits long, straight rip cuts, while a blade angle of 45° or 90° allows for greater capacity for cutting long materials. The band saw includes a three-position clamping mechanism that allows for proper tensioning of the saw blade depending on the degree of twist. With the blade unlocked, a lever arm can be positioned to actuate the upper and lower blade guides to twist the blade. With the blade positioned and tensioned, the actuated twisting arm can be swung out of the way, allowing for full cutting capacity.

[0007] Fig. Figure 1 shows an embodiment of a band saw 10 according to the present disclosure. The band saw 10 of Fig. 1 is a vertical band saw. The teachings of this disclosure can be applied to other embodiments of band saws, such as horizontal band saws, portable hand saws, and the like. The band saw 10 comprises a frame 12, a band saw blade 14, wheels 16, 18, a drive system (not shown), blade guide assemblies 20, 22, and a table 24.

[0008] The frame 12 provides the structure that supports and positions the wheels 16, 18, the guides 20, 22, and the table 24 relative to one another. The frame 12 is typically made of metal such as cast iron or welded steel and can have any suitable configuration. The wheels 16, 18 support and position the band saw blade 14 and define the blade's path of movement. The blade body 14 is designed to lie flat against the outer surface of the wheels 16, 18 as it wraps around them. The wheels 16, 18 define a tangential wheel contact plane with the blade, which runs parallel to the wheels' axes of rotation.

[0009] At least two wheels are used to support and guide the blade. For a vertical band saw, as in Fig. As shown in Figure 1, the two wheels 16 and 18 comprise an upper wheel 16 and a lower wheel 18. The frame 12 forms housings for the wheels 16 and 18, which are referred to as wheel housings. The band saw 10 includes a blade tensioning mechanism 26, which allows the blade to be tensioned for sawing and the blade tension to be released for removal and replacement as needed. As part of the tensioning system, the upper wheel 16, and sometimes the lower wheel 18, is designed to be raised and lowered to regulate the tension of the blade 14. The blade tensioning mechanism 26 includes a mechanism, such as a wheel or a lever, that can adjust the vertical position of the wheel 16 to achieve the desired degree of tension in the blade.

[0010] The lower wheel 18 is coupled to the drive system and is used to rotate the blade. The drive system includes a motor (not shown) which can be housed in the wheel housing. The lower wheel 18 can be mounted directly on the motor shaft or coupled to the shaft via pulleys and a belt.

[0011] When wound around the wheels 16, 18, the bandsaw blade 14 has two straight, tensioned sections 28, 30 extending on opposite sides between the wheels 16, 18. One of these sections is the rear section 28, which is enclosed in a support 32 of the frame 12 extending between the upper and lower wheel housings. The front section 30 is used for cutting and is therefore at least partially exposed. The table 24 is arranged to support a workpiece in the path of movement of the exposed section 30 of the blade 14. The table 24 includes a slot (not shown) through which the blade extends. The table 24 can be mounted on a pivot pin, which allows the table to be tilted or inclined about an axis of inclination. The pivot pin is designed such that the axis of inclination is parallel to the plane of the blade 14.

[0012] The open space between the upper wheel housing and the table is referred to here as cutting zone 34. The blade guide assemblies 20, 22 are arranged on both sides of cutting zone 34 (i.e., above and below) and are designed to enclose the blade 14 in order to maintain a precise cutting path through the cutting zone. As shown in Fig. As shown in Figures 3-5, each blade guide assembly 20, 22 comprises two side guides 36, 38 and a push guide 40. The side guides 36, 38 are arranged on both sides of the blade 14 and together serve to control the angle of the blade 14 through the cutting zone 34. The push guide 40 supports the rear blade in resisting the feed force (i.e., the force of the workpiece being advanced against the blade). The side guides 36, 38 and the push guide 40 can be individually adjustable relative to each other to accommodate different blade widths and thicknesses.

[0013] At least one of the guide arrangements 20, 22 is designed to be vertically adjustable in order to widen or narrow the distance between the guide arrangements. In the embodiment of Fig. 1 The upper guide assembly 20 is vertically adjustable. This allows the upper guide assembly to be positioned close to the upper surface of a workpiece to be cut, ensuring maximum blade control in the cutting zone. The band saw can include a blade guard 42 that extends downwards from the upper wheel housing and covers an upper portion of the blade.

[0014] According to the present disclosure, the upper and lower guide arrangements 20, 22 are designed such that they pivot or rotate about a longitudinal axis of the blade 14 to adjust the angle of the blade relative to a wheel contact plane 50 ( Fig. 3-5) in the cutting zone. Each of the upper and lower guide arrangements 20, 22 is designed to be selectively and releasably locked at at least two different angular positions relative to the longitudinal axis of the blade.

[0015] When the upper and lower guide arrangement 20, 22 are arranged in a first angular position, as in Fig. As shown in Figure 3, the blade 14 is held in place with the blade plane 48 at a position of 0° relative to the wheel contact plane 50. In other words, the blade plane 48 is essentially coplanar with the wheel contact plane 50 in the first angular position. The upper and lower guide arrangement can be pivoted or rotated from the first angular position to at least one second angular position, as shown in Figure 3. Fig. 4 and Fig. 5 shown.

[0016] In the second angular position, the blade plane 48 can be angled at 45° relative to the wheel contact plane 50, as shown in Fig. 4 shown, or 90°, as in Fig. 5 shown, or can be placed in any position between these two. Each of the upper and lower guide arrangements 20, 22 is designed such that it can be detachably locked at the first and second angular positions. The upper and lower guide arrangements 20, 22 can be designed such that they can be pivoted to more than two angular positions and detachably locked there. The upper and lower guide arrangements can, for example, be designed such that they can be pivoted into a second angular position, as shown in Figure 5, or placed in any position between these two. Fig. 4 shown, as well as in a third angular position, as in Fig. 5 shown, can be swivelled.

[0017] The guide arrangements 20, 22 can be designed such that they can be pivoted into the various angular positions in a suitable manner and releasably locked there. In one embodiment, the guide arrangements 20, 22 are designed such that they are locked in a fixed position while the blade is tensioned and can only be pivoted when the tension on the blade is released, for example by the tensioning mechanism 26.

[0018] As in Fig. 1 and Fig. As shown in Figure 2, the guide arrangements 20, 22 can be coupled to a lever arm 52 to make changing the position of the guide arrangements 20, 22 more efficient. The lever arm is coupled to both guide arrangements 20, 22. The lever arm can be manually pivoted by a band saw operator using the handle 54, which in turn causes a pivoting movement of the guide arrangements 20, 22 between the different angular positions.

[0019] As in Fig. As can be seen in Figure 1, the lever arm 52 can be shaped in such a way that it minimally interferes with the cutting capacity of the band saw. For example, the lever arm 52 can have a lateral U-shape designed to extend around the cutting zone of the band saw. To ensure that the lever arm 52 does not interfere with the cutting capacity of the band saw, its design can decouple it from the guide arrangements 20, 22, so that the lever arm 52 can be returned to a rest position when not in use. As shown in Figure 1, the lever arm 52 can be shaped in such a way that it minimally interferes with the cutting capacity of the band saw. Fig. As shown in Figure 1, the lever arm has, for example, hinges 56 that allow the lever arm 52 to be folded out of the way when not in use. In alternative embodiments, the lever arm 52 can be detached from the guide arrangements 20, 22 when not in use.

[0020] As is well known in engineering, twisting the blade changes its path length and thus its tension requirements. Therefore, the blade can have different tension requirements in orientations of 90°, 45°, and 0°. To facilitate blade tensioning in different orientations, the blade tensioning mechanism 26 can be designed to have a different target tension position for each orientation. For example, the blade tensioning mechanism has a first position that tensions the blade when it is at 0°, a second position that tensions the blade when it is twisted, for example, at 45°, and a third position that releases the tension from the blade so that it can be removed and the blade guide assemblies can be pivoted.

[0021] The blade tensioning mechanism 26 can include a lever configured to change the position of the upper wheel 16 by predetermined amounts in order to adjust the blade tension for each setpoint position. In alternative embodiments, the blade tensioning mechanism 26 can include an automatic tensioning mechanism that uses an adjustable, previously known spring to automatically adjust the position of the upper wheel in order to accommodate torsion-induced blade length variations with minimal to no change in blade tension.

[0022] As noted above, the table 24 can be designed to be tilted about an axis of inclination. The table is designed such that the axis of inclination is parallel to the plane of the blade. In one embodiment, the table 24 can be rotatably connected to the lower blade guide assembly 22, so that the table 24 rotates when the lower blade guide assembly 22 is pivoted between the first and second positions. This ensures that the axis of inclination remains parallel to the plane of the blade when the blade angle is changed through the cutting zone.

[0023] The disclosure has been described and illustrated in detail in the drawings and the preceding description, but this is to be considered illustrative and not limiting. It is understood that only the preferred embodiments have been presented and that it is desired to also protect all modifications, alterations, and further applications that fall within the scope of the disclosure.

Claims

[1] Band saw (10) comprising: a frame (12); a first wheel (16) and a second wheel (18) which are supported by the frame (12); a band saw blade (14) which is looped around the first wheel (16) and the second wheel (18) and is held under tension between the first wheel (16) and the second wheel (18); a first blade guide arrangement (20) and a second blade guide arrangement (22) which guide the band saw blade (14) through a cutting zone (34), wherein the first blade guide arrangement (20) is arranged on a first side and the second blade guide arrangement (22) is arranged on a second side of the cutting zone (34); and a lever arm (52) that is coupled to both the first blade guide assembly (20) and the second blade guide assembly (22), wherein the lever arm (52) is designed to be moved manually by an operator of the band saw, wherein the movement of the lever arm (52) moves the first blade guide assembly (20) and the second blade guide assembly (22) simultaneously between the first angular position and the second angular position, wherein the lever arm (52) is designed such that it is decoupled from the first blade guide arrangement (20) and the second blade guide arrangement (22) and is moved to a rest position, wherein the first wheel (16) and the second wheel (18) define a tangential wheel contact plane that extends through the cutting zone (34), wherein the first blade guide arrangement (20) and the second blade guide arrangement (22) are each mounted for a pivoting movement about a rotational axis between a first angular position and a second angular position, wherein the first blade guide arrangement (20) and the second blade guide arrangement (22) are each selectively lockable in the first angular position and the second angular position, wherein in the first angular position the first and the second blade guide arrangement (20, 22) hold the band saw blade (14) at a first angle to the wheel contact plane and wherein in the second angular position the first and the second blade guide arrangement (20, 22) hold the band saw blade (14) at a second angle to the wheel contact plane, the second angle being different from the first angle. [2] Band saw (10) according to claim 1, wherein the first angle is 0° and the second angle is at least 45°. [3] Band saw (10) according to claim 1, wherein the first and the second leaf guide arrangement (20, 22) can each be pivoted to a third angular position and selectively locked at this position, and wherein in the third angular position the first and the second blade guide arrangement (20, 22) hold the band saw blade (14) at a third angle to the wheel contact plane, the third angle differs from the first angle and the second angle. [4] Band saw (10) according to claim 3, wherein the first angle is 0°, the second angle is 45° and the third angle is 90°. [5] Band saw (10) according to claim 1, further comprising: a blade tensioning mechanism (26) which is operationally coupled to at least one of the wheels (16, 18) and has at least three tensioning positions, wherein the blade tensioning mechanism (26) has a first position for tensioning the blade (14) when the blade is aligned in the cutting zone (34) at the first angle, a second position for tensioning the blade (14) when the blade (14) is aligned in the cutting zone (34) at the second angle, and a third position for releasing the tension in the blade (14). [6] Band saw (10) according to claim 1, further comprising: a table (24) for supporting a workpiece to be cut by the band saw blade (14) in the cutting zone (34), wherein the first leaf guide arrangement (20) is positioned above the table (24) and the second leaf guide arrangement (22) is positioned below the table (24), and wherein the table (24) is rotatably coupled to the second sheet guide arrangement (22) so that the table (24) rotates with the second sheet guide arrangement (22) between the first angular position and the second angular position. [7] Band saw (10) according to claim 6, wherein the table (24) is designed to be tilted about an axis of inclination, the axis of inclination intersecting the cutting path when the second blade guide arrangement (22) is in both the first angular position and the second angular position. [8] Band saw (10) comprising: a frame (12); a first wheel (16) and a second wheel (18) which are supported by the frame (12); a band saw blade (14) which is looped around the first wheel (16) and the second wheel (18) and is held under tension between the first wheel (16) and the second wheel (18); and a first blade guide arrangement (20) and a second blade guide arrangement (22) which guide the band saw blade (14) through a cutting zone (34), wherein the first blade guide arrangement (20) is arranged on a first side and the second blade guide arrangement (22) is arranged on a second side of the cutting zone (34); and a table (24) for supporting a workpiece to be cut by the band saw blade (14) in the cutting zone (34), wherein the first leaf guide arrangement (20) is positioned above the table (24) and the second leaf guide arrangement (22) is positioned below the table (24), and wherein the table (24) is rotatably coupled to the second blade guide arrangement (22) so that the table (24) rotates with the second blade guide arrangement (22) between the first angular position and the second angular position; wherein the first blade guide arrangement (20) and the second blade guide arrangement (22) are each rotatable about an axis of rotation between a first angular position and a second angular position, wherein the first wheel (16) and the second wheel (18) define a tangential wheel contact plane that extends through the cutting zone (34), wherein the first blade guide arrangement (20) and the second blade guide arrangement (22) are each mounted for a pivoting movement about a rotational axis between a first angular position and a second angular position, wherein the first blade guide arrangement (20) and the second blade guide arrangement (22) are each selectively lockable in the first angular position and the second angular position, wherein in the first angular position the first and the second blade guide arrangement (20, 22) hold the band saw blade (14) at a first angle to a wheel contact plane, and wherein in the second angular position the first and the second blade guide arrangement (20, 22) hold the band saw blade (14) at a second angle to the wheel contact plane, the second angle being different from the first angle. [9] Band saw (10) according to claim 8, wherein the first angle is 0° and the second angle is at least 45°. [10] Band saw (10) according to claim 8, further comprising: a lever arm (52) that is coupled to both the first blade guide arrangement (20) and the second blade guide arrangement (22), wherein the lever arm (52) is designed to be moved manually by an operator of the band saw (10), wherein the movement of the lever arm (52) moves the first blade guide assembly (20) and the second blade guide assembly (22) simultaneously between the first angular position and the second angular position. [11] Band saw (10) according to claim 10, wherein the lever arm (52) is designed to be decoupled from the first blade guide arrangement (20) and the second blade guide arrangement (22) and to be moved to a rest position. [12] Band saw (10) comprising: a frame (12); a first wheel (16) and a second wheel (18) which are supported by the frame (12); a band saw blade (14) which is looped around the first wheel (16) and the second wheel (18) and is held under tension between the first wheel (16) and the second wheel (18); and a first blade guide arrangement (20) and a second blade guide arrangement (22) which guide the band saw blade (14) through a cutting zone (34), wherein the first blade guide arrangement (20) is arranged on a first side and the second blade guide arrangement (22) is arranged on a second side of the cutting zone (34); and a lever arm (52) that is coupled to both the first blade guide arrangement (20) and the second blade guide arrangement (22), wherein the lever arm (52) is designed to be moved manually by an operator of the band saw (10), wherein the first blade guide arrangement (20) and the second blade guide arrangement (22) are each rotatable about an axis of rotation between a first angular position and a second angular position, wherein in the first angular position the first and the second blade guide arrangement (20, 22) hold the band saw blade (14) at a first angle to a wheel contact plane, wherein in the second angular position the first and the second blade guide arrangement (20, 22) hold the band saw blade (14) at a second angle to the wheel contact plane, the second angle being different from the first angle, wherein the movement of the lever arm (52) moves the first blade guide assembly (20) and the second blade guide assembly (22) simultaneously between the first angular position and the second angular position, and wherein the lever arm (52) is designed such that it is decoupled from the first blade guide arrangement (20) and the second blade guide arrangement (22) and is moved to a rest position.

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