Band saws

Abstract

Band saws for cutting and shaping workpieces of various materials are disclosed. Adjustable fence mechanisms are disclosed for providing workpiece support surfaces aligned to the blade. Adjustable blade guards are disclosed to shield an operator from the blade. Adjustable blade guide mechanisms are disclosed for supporting the blade against lateral displacement. Pivoting rail mechanisms are disclosed for supporting a fence. Table alignment mechanisms are disclosed for aligning two sections of a band saw table. Cabinet door latch mechanisms are disclosed with electronic sensors to detect whether a cabinet door is latched. Adjustable table latch mechanisms are disclosed. Table insert mechanisms are disclosed. Cabinet skylights are disclosed. Various other components, mechanisms, combinations, assemblies, features, and methods of band saws are disclosed.

Description

BAND SAWSCROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] This application claims the benefit of and priority from U.S. Provisional Patent Application Serial No. 63 / 637,769, filed April 23, 2024, the complete disclosure of which is incorporated herein by reference.TECHNICAL FIELD

[0002] The present disclosure relates to power tools, and more particularly to band saws.BACKGROUND

[0003] A power tool such as a band saw is used to cut a workpiece, such as a piece of wood or metal, to a desired size or shape. A band saw typically includes two or more spacedapart wheels and a band blade mounted on the wheels to move in a continuous loop. At least one motor is typically coupled to drive one or more of the wheels and thereby drive the blade. The blade passes through or near a work surface. An operator uses a band saw by placing a workpiece on the work surface and moving the workpiece into contact with the moving blade so that the workpiece is cut or shaped as desired. Band saws often include one or more components or mechanisms to improve the ease, quality, and reliability of the cutting / shaping operation, as well as to allow different types of band blades to be installed for different cutting operations. Such components or mechanisms can include blade guides, fences, rails, table inserts, and etc. Some band saws include cabinets which at least partially enclose the wheels to reduce the hazard caused by moving mechanical components. Such cabinets may include doors to allow an operator to access the wheels when performing maintenance or repair operations such as changing the blade. Additionally, band saws often include blade guards which help to shield portions of the blade which are outside the cabinet.

[0004] Band saws are commonly used in a wide variety of applications, hobbies, and commercial operations. Just a few examples include furniture making and cabinetry, home and building construction, crafts, metal cutting, meat cutting, and etc. Band saws come in sizes ranging from large, stationary, industrial band saws equipped with large motors to drive large blades, to small, lightweight, table-top band saws with small motors and blades. The larger band saws include induction motors and cast-iron parts, and typically weigh well over 100 pounds. The smaller band saws are often small and light enough to be lifted by a single person. Some band saws are intended for use in cutting wood and other soft materials, while other band saws areintended for cutting steel, aluminum, and other metals. Another category of band saws is designed for use in food processing such as meat cutting.

[0005] This specification describes components, mechanisms, assemblies, structures, and methods relevant to power tools, and more particularly to band saws of all sizes, types, and intended uses.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Fig. 1 shows a front perspective view of an exemplary band saw.

[0007] Fig. 2 shows a rear perspective view of the exemplary band saw.

[0008] Fig. 3 shows a cropped perspective view of the trunnion assembly of the exemplary band saw.

[0009] Fig. 4 shows a front perspective view of the exemplary band saw with the cabinet doors open.

[0010] Fig. 5 shows a closeup perspective view of the upper wheel of the exemplary band saw.

[0011] Fig. 6 shows a closeup perspective view of the lower wheel of the exemplary band saw.

[0012] Fig. 7 shows a closeup perspective view of the lower wheel of the exemplary band saw, in which the cabinet is removed to show the coupling between the motor and the lower wheel.

[0013] Fig. 8 shows a cropped front view of the exemplary band saw with the task light assembly and lower blade guide housing removed.

[0014] Fig. 9 shows a cropped perspective view of the exemplary band saw with the blade guard assembly removed.

[0015] Fig. 10 shows a perspective, partially exploded view of the upper blade guide assembly of the exemplary band saw.

[0016] Fig. 11 shows a cross section view of an exemplary mounting post assembly.

[0017] Fig. 12 shows a top view of the upper blade guide assembly of Fig. 9, with some components in cross section.

[0018] Fig. 13 shows a perspective view of the lower blade guide assembly of the exemplary band saw with the lower blade guide housing cover in an open position.

[0019] Fig. 14 shows a perspective, partially exploded view of the lower blade guide assembly of Fig. 13.

[0020] Fig. 15 shows a cropped, perspective view of the exemplary band saw focusing on the exemplary fence assembly.

[0021] Fig. 16 shows a perspective view of the exemplary fence assembly, partially exploded to illustrate the major subassemblies.

[0022] Fig. 17 shows a front view of the workpiece guide assembly of the exemplary fence assembly.

[0023] Fig. 18 shows a perspective exploded view of the workpiece guide assembly of Fig. 17.

[0024] Fig. 19 shows a cropped side view of the exemplary fence assembly mounted on the rail of the exemplary band saw.

[0025] Fig. 20 shows a perspective view of the carriage assembly of the exemplary fence assembly.

[0026] Fig. 21 shows a partial exploded view of the positioning plate assembly of the exemplary fence assembly.

[0027] Fig. 22 shows a perspective view of the bottom of the positioning plate of Fig. 21.

[0028] Fig. 23 shows a front cross-section view of the exemplary fence assembly.

[0029] Fig. 24 shows another perspective, partial exploded view of the positioning plate assembly of Fig. 21.

[0030] Fig. 25 shows a closeup, cropped, cross-sectional view of the attachment of the positioning plate to the carrier base.

[0031] Fig. 26 shows a side cross-section view of the exemplary fence assembly with several components of the carriage assembly removed for clarity.

[0032] Fig. 27 shows a schematic illustration of a fence assembly having a drift angle adjustment origin proximate the rail.

[0033] Fig. 28 shows a schematic illustration of a fence assembly having a drift angle adjustment origin proximate the blade.

[0034] Fig. 29 shows a cropped, top view of the positioning plate assembly and carriage assembly of Fig. 26, with the drift clamp handle in the unclamped position.

[0035] Fig. 30 shows a cropped, top view of the positioning plate assembly and carriage assembly of Fig. 26, with the drift clamp handle in the clamped position.

[0036] Fig. 31 shows the table and rail assembly of the exemplary band saw with the rail in its operational position.

[0037] Fig. 32 shows the same view as Fig. 31 , but with the rail in its nonoperational position.

[0038] Fig. 33 shows a perspective, exploded view of the table and rail assembly of Fig. 31.

[0039] Fig. 34 shows a cross section view of the table and rail assembly of Fig. 31 where the cross section is taken through the center of the pivot bushing.

[0040] Fig. 35 shows a perspective, exploded view of the pivot connection and table alignment mechanisms of the table and rail assembly of Fig. 31 , with closeup circles showing the interface between the pivot bushing and pivot bracket.

[0041] Fig. 36 shows a cropped, perspective view of the underside of the table and rail assembly of Fig. 31.

[0042] Fig. 37 shows a cropped rear view of the table and rail assembly of Fig. 31 with the rail in its operational position and taken in cross section through the crossbar.

[0043] Fig. 38 shows the same view as Fig. 37, but with the rail in its nonoperational position.

[0044] Fig. 39 shows a cropped, perspective view of the lower portion of the exemplary band saw including the lower door handle assembly with the lower cabinet door in the closed position.

[0045] Fig. 40 shows an exploded view of the lower cabinet door handle assembly.

[0046] Fig. 41 shows an alternative exploded view of some of the components of the lower door handle assembly.

[0047] Fig. 42 shows a cross section view of the door latch mechanism on the lower cabinet door.

[0048] Fig. 43 shows a cross section view of the lower cabinet door when the door is closed and latched.

[0049] Fig. 44 shows the same cross section as Fig. 43, but with the door unlatched.

[0050] Fig. 45 shows an exemplary schematic circuit for controlling a band saw motor.

[0051] Fig. 46 shows an alternative schematic circuit for controlling a band saw motor.

[0052] Fig. 47 shows a cropped, perspective view of the exemplary band saw with the blade guard door in the open position.

[0053] Fig. 48 shows a partially exploded view of several subassemblies of the exemplary band saw including the blade guard assembly, the elevation assembly, and the task light assembly.

[0054] Fig. 49 shows an exploded view of the blade guard assembly.

[0055] Fig. 50 shows a front view of a blade guard shield plate.

[0056] Fig. 51 shows a side view of the blade guard assembly when the blade guard assembly is at a relatively low position above the band saw table.

[0057] Fig. 52 shows a side view of the blade guard assembly when the blade guard assembly is at a position above the band saw table that is higher than the position shown in Fig. 51.

[0058] Fig. 53 shows a closeup, cropped cross-section of the left side of the blade guard assembly of Fig. 52.

[0059] Fig. 54 shows a cropped view of the left side of the blade guard assembly with the blade guard base frame in sectioned view to reveal the interaction of the shield plates with the base frame.

[0060] Fig. 55 shows an exploded view of the task light assembly with the electrical cable and screws removed.

[0061] Fig. 56 shows a cross-section of the task light assembly.

[0062] Fig. 57 shows a cropped, perspective view of an exemplary table latch mechanism.

[0063] Fig. 58 shows a cropped, sectional view of the table latch mechanism of Fig. 57.

[0064] Fig. 59 shows a perspective view of an exemplary table insert assembly.

[0065] Fig. 60 shows a perspective view of an exemplary temporary positioning block.

[0066] Fig. 61 shows a different perspective view of the exemplary positioning block ofFig. 60.

[0067] Fig. 62 is a cropped, perspective view of the exemplary positioning block on a band saw prior to installation of the table.

[0068] Fig. 63 is a cropped, perspective view of the exemplary positioning block on a band saw with the table supported by the positioning block.

[0069] Fig. 64 is a different cropped, perspective view of the exemplary positioning block on a band saw after the table has been mounted to the band saw.DETAILED DESCRIPTION

[0070] I . Introductory Information:

[0071] The present drawings and written disclosure illustrate and describe various exemplary embodiments of power tools, mechanisms, components, circuits, processes, and methods. The particular embodiments which are illustrated and disclosed herein are not to be considered in a limiting sense as numerous variations are possible. Rather, the various exemplary embodiments depicted in the drawings and described in detail below are intended to illustrate specific examples and implementations in a variety of different contexts. It will be understood bythose of skill in the art that many different variations, modifications, alternatives, and equivalents of these particular exemplary embodiments are possible. Therefore, the drawings and written disclosure are not intended to limit the scope of the claims to the particular forms, arrangements, components, and / or configurations depicted and described herein. Instead, the claims are intended to cover all such variations, modifications, alternatives, and equivalents which are described and suggested within the scope and spirit of the disclosure as it would be understood by those of skill in the art.

[0072] While references to “exemplary embodiment”, “alternative embodiments”, “other embodiments”, etc., may appear throughout the written disclosure, repeated occurrences of such references are not intended necessarily to refer to the same embodiment(s). Rather, such references should be understood in the context in which they are presented and with reference to the figures and components with which they are associated within the narrative of the disclosure. Furthermore, reference to certain embodiments is not intended to exclude other embodiments since particular components, elements, circuits, structures, assemblies, processes, and methods described herein may be combined and / or modified in any manner that is suitable and consistent with the disclosure.

[0073] The written disclosure and / or the accompanying claims may refer to structural elements as being “configured to,” or “adapted to,” perform one or more tasks, operations, or functions. Such elements may be referred to as “components,” “circuits,” “assemblies,” “mechanisms,” etc. It should be understood that when such an element is described as being “configured to” or “adapted to” perform such a task or etc., this phrasing is intended to refer to a physical object or structure such as an electronic component (e.g., resistor, capacitor, cable, processor, etc.), or a mechanical component (e.g., fastener, arm, bracket, shaft, mount, housing, etc.), or a plurality of such components interconnected or combined into a circuit, mechanism, or assembly. Furthermore, the phrasing “configured to” or ’’adapted to” perform a particular task, operation, or etc., is intended to indicate that the structural component or combination of components is arranged, positioned, selected, programmed, connected, combined, and / or designed to perform the particular task or operation stated. Thus, for example, the phrase “a processor component configured to receive an input from a user-input component” means a physical processor with one or more input nodes which may be connected either directly, or indirectly through additional circuit components, to the output of a physical switch, button, knob, or similar component which is operable by a person to produce electrical signals. And further that the input node(s) of the processor are capable of receiving signals of the type which the userinput component produces, so that the processor, while executing software instructions stored inmemory is capable of recognizing the signal for its intended purpose and executing further instructions in response to the signal as determined by the stored software. Likewise, the phrase “a motor configured to drive the cutting tool” means a motor with sufficient output power to move the cutting tool in a manner and at a speed appropriate for the corresponding power tool to cut or shape workpieces as intended. Therefore, it should be understood that all references herein of some particular element being “configured to” or “adapted to” perform some operation, task, or function refers to a physical object and not to some intangible element, entity, or process.

[0074] In addition, the term “configured to” or “adapted to” does not mean “configurable to” or “adaptable to.” Thus, for example, an unprogrammed processor that is devoid of executable software instructions may be configurable to perform a task, but it should not be considered as “configured to” perform the task within the context of the present disclosure. Instead, if a processor is referred to herein as “configured to” perform a task, that phrasing means the processor includes the necessary executable software instructions, as well as any necessary processing functionality such as analog-to-digital conversion or etc., to perform the referenced task.

[0075] To the extent the phrase “in response to” is used herein, the phrase is intended to describe one more factors that produce an effect. However, the phrase is not intended to eliminate the possibility that additional and / or different factors may affect whether or how the effect is produced. Thus, for example, the phrase “the control circuit is configured to start the motor in response to inputs by the operator” does not mean that the input from the operator is necessarily the only input or condition necessary to start the motor. Instead, the phrase is intended to cover the situation where the motor is started solely in response to input by the operator, as well as the situation where the motor is started only when one or more additional conditions or inputs are present in combination with the input by the operator. Furthermore, the phrase is also not intended to convey that the motor can only be started in response to the input from the operator, as other conditions and / or inputs may also cause the motor to start independent of the input from the operator.

[0076] If used herein, the terms “first,” “second,” etc., when used to modify structural elements, are not intended to describe any temporal or spatial order, hierarchy, or priority, unless such order, hierarchy, or priority is expressly stated. Thus, for example, the terms “first processor” and “second processor” do not, unless otherwise stated, imply that the component referred to as the “first processor” has any priority or control over the component referred to as the “second processor.” Furthermore, the terms are not intended to imply that the two processors are either identical or non-identical unless explicitly described as such. Instead, the terms are solely intended to convey the presence of two, separate physical processors.

[0077] Unless otherwise stated explicitly, the terms “user” and “operator,” when used herein in reference to using or operating a mechanism such as a power tool, are identical and interchangeable. In contrast, the term “person” means any person whether or not the person is using or operating the mechanism in question.

[0078] In the drawings and written disclosure herein, numerous specific details are described for a variety of exemplary embodiments to provide a complete and thorough understanding to those of skill in the art. Nevertheless, those of skill in the art will recognize that many aspects of the present disclosure can be practiced without one or more of the specific details. In some embodiments, well-known and / or readily available components, circuits, structures, assemblies, signals, software instructions, and techniques may have not been shown or described in detail to avoid unhelpful complexity which might hinder comprehension of the present disclosure in its entirety. Similarly, unnecessary details and / or selected tangent surface boundary lines may be removed from some drawings of physical components and assemblies to accentuate the structure of the components and assemblies. Additionally, certain figures may include cropped and / or magnified areas to clearly illustrate selected portions of a larger view. Furthermore, drawing requirements and size constraints may require that larger and / or more complex components, features, assemblies, processes, etc., be divided into multiple sections and illustrated using multiple drawings. Such drawings should be viewed and understood as an undivided whole.

[0079] II. Detailed Disclosure:

[0080] One exemplary embodiment of a band saw is shown in Figs. 1-2 and indicated generally at 10. Band saw 10 includes a support structure 12 in the form of a metal housing or cabinet. In this exemplary embodiment, the support structure is constructed from multiple pieces of steel sheet metal and tubing which are attached by various mechanisms such as welding and fasteners to form a cabinet assembly. The cabinet assembly generally includes a base portion 14 configured to stably support the band saw on the floor, a lower cabinet section 16, an upper cabinet section 18, and a column or riser 20 which supports the upper cabinet section above the lower cabinet section. Lower section 16 includes a lower door 22 and upper section 18 includes an upper door 24. The lower and upper doors are openable by an operator to access the internal mechanisms of the band saw. While exemplary support structure 12 is in the form of a substantially enclosed cabinet of steel, it will be appreciated that many variations are possible within the scope of the disclosure such as cabinets made wholly or partially of other materials, open-frame support structures, bench-top housings, etc.

[0081] Exemplary band saw 10 also includes a table 26 supported by the support structure and adapted to support workpieces during cutting or shaping. Exemplary table 26 is formed of cast iron and includes a removable extension wing 28 to provide additional surface area for supporting workpieces. Alternatively, the table may be a unitary component and may be formed of other materials such as aluminum, steel, stone, plastic, etc.

[0082] T urning attention briefly to Fig. 3, it can be seen that table 26 is mounted to cabinet12 by a trunnion assembly 30 that includes a trunnion block 32 and one or more trunnion brackets 34. Trunnion block 32 includes arcuate tracks or ways 36 which engage and support mating arcuate surfaces 38 on trunnion brackets 34. Arcuate tracks 36 and surfaces 38 are configured such that the center axis of the concentric arcs is coincident with the upper surface 40 of table 26. Trunnion assembly 30 mounts the table to cabinet 12 while allowing the table to be selectively tilted relative to the cabinet about the axis of the trunnion assembly arcs. Once the angle of the table relative to the cabinet has been set to the desired tilt angle, the table can be locked against further tilting by a clamp handle 42 which operates a clamping mechanism 44 to clamp the trunnion brackets tightly to the trunnion base. The axis of the trunnion assembly arcs is also referred to herein as the “tilt axis” of the table.

[0083] Returning attention to Figs. 1-2, it can be seen that table 26 includes an opening which is filled by a removable table insert 46. A rail 48 is mounted to the front of the table and extends parallel to the front edge of the table. A fence assembly 50 is mounted to slide along the rail and rest on the upper surface of the table. Fence assembly 50 is used to guide workpieces in a straight line during shaping or cutting. As needed, the fence can be removed from the rail and table by the operator.

[0084] Referring now to Figs. 4-7, some of the internal mechanisms of the exemplary band saw can be seen. An upper wheel 52 is mounted to rotate on an upper arbor 54, which is supported by upper section 18. A lower wheel 56 is mounted on a lower arbor 58 which is rotatably supported by lower section 16. A wheel pulley 60 is bolted (or fastened by alternative mechanisms) to the lower wheel so that the pulley, wheel, and lower arbor rotate together. Wheels 52 and 56 typically have outer diameters in the range of 10 to 24 inches, though other sizes are also possible within the scope of the present disclosure.

[0085] Band saw 10 also includes an electrically powered motor 62 which is supported by cabinet 12. Exemplary motor 62 is an AC induction-type motor, although other motor types may be used within the scope of the disclosure, including universal motors, DC motors, brushless motors, hydraulic motors, etc. Motor 62 includes a drive shaft 64 which rotates in a clockwise direction (as viewed from the front of the band saw) when the motor is powered. A motor pulley66 is mounted to drive shaft 64, and a motor belt 68 is mounted in a loop over the arbor and motor pulleys. Thus, motor 62 is coupled to the lower wheel by the pulleys and belt so that the lower wheel is driven in a clockwise direction (as viewed in Fig. 6) by the motor when the motor is powered. In the exemplary embodiment, the motor is configured to spin at approximately 1 ,720 rpm with a 60Hz electrical supply, and the arbor and motor pulleys are sized so that the lower wheel spins at approximately 772 rpm. Alternative embodiments may use different speeds, voltages, and / or frequencies as appropriate for the intended use of the band saw or the local electrical supply.

[0086] A band blade 70 is mounted around the upper and lower wheels. Blade 70 is formed as a continuous, flat strip or ribbon with an inner surface that lies flat along the outer rims of the wheels. The front edge of the blade includes a plurality of teeth adapted for cutting workpieces. The teeth may be formed from the same material as the body of the blade or may be formed of a different material such as tungsten carbide, etc. Band saw blades are commonly available in a variety of different sizes. Each blade has a circumference which generally corresponds to the diameter of the band saw wheels on which the blade will be used. In addition to the circumference, each band saw blade has a width and a thickness. The different combinations of widths and thicknesses offer different cutting characteristics which may be desirable for specific cutting operations.

[0087] In the exemplary embodiment, the rims of the wheels include an outer layer or covering, commonly referred to as a tire, although the tires may be omitted in alternative embodiments. Upper tire 72 is removably mounted on the outer rim of upper wheel 52, and lower tire 74 is removably mounted on lower wheel 56. Thus, blade 70 is mounted over the tires. The tires are typically made of a rubber or other material that is configured to grip or frictionally engage the blade and wheels.

[0088] The upper and lower arbors are aligned so that the axes of the arbors are generally parallel. Additionally, the upper and lower wheels are mounted on the respective arbors so that the front edges of the wheels are approximately aligned along a common plane. The precise alignment of one or more of the wheels is often adjustable to ensure the blade runs over the spinning wheels without substantial movement in an axial direction. In other words, the relative alignment of the wheels is typically adjustable so that the blade does not move off the wheels when the wheels are rotating. Such movement (or non-movement) of the blade in an axial direction on the wheels is often referred to as the blade “tracking,” since the intended result is for the blade to run in a substantially stationary track over the wheels.

[0089] The distance between the axes of the upper and lower arbor is adjustable to increase or decrease the amount of tension on the blade. When preparing the band saw for cutting operations, the blade tension is usually adjusted to a level at least sufficient to ensure that the blade does not slip over the surface of the tires during normal operation. As a result, when motor 62 drives lower wheel 56, blade 70 is driven in a clockwise loop by the frictional contact between the blade and the lower tire. Furthermore, the friction between the blade and the upper tire causes the movement of the blade to drive the upper wheel in a clockwise direction. Thus, the motor drives the rotation of both wheels as well as the movement of the blade in its continuous path over the wheels. When, as in the exemplary embodiment, the upper and lower wheels have the same diameter, the upper and lower wheels will move at substantially the same rotational speed. The linear speed of the blade in its path around the wheels will be determined by the rotational speed and diameter of the wheels.

[0090] When the blade is mounted on the wheels, it forms an elongate loop with generally straight sections extending between the left and right sides of the wheels. The straight section of the blade on the left extends between the upper and lower wheels within column 20 and is thus enclosed within cabinet 12 during normal operation. The straight section of the blade on the right side of the wheels runs down from upper cabinet section 18 through a blade guard assembly 76. The blade exits the bottom of the blade guard assembly and passes through a slot in table insert 46 and then enters lower cabinet section 16. The sides of the blade where it passes through the table insert are substantially parallel to, and approximately coplanar with, the tilt axis of the table. As a result, the blade continues to pass through the slot in the table insert when an operator tilts the table.

[0091] An opening in the top of the cabinet is covered by a clear plastic window or skylight 78 to allow light into the upper section of the cabinet. The skylight allows exterior light to illuminate the right side of the upper wheel. This illumination enables an operator more easily to view the position and tracking of the blade when looking through the blade view window 79 which is mounted over an opening in the right side of the upper section.

[0092] Band saw 10 also includes a switch box assembly 80 which is configured to control the supply of electrical power to motor 62 in response to inputs from an operator. The band saw is connected to a supply of electrical power via a power cord 82 (shown in Fig. 2). One end (not shown) of power cord 82 is configured to connect to a local supply of electrical power such as a standard electrical outlet. The opposite end of the power cord is connected to a power module assembly (not shown) located in lower cabinet section 16. The power module assembly is connected to supply electrical power to the switch box assembly which is mounted in column 20so as to be accessible by an operator. The switch box assembly includes at least one switch or other user input component which can be actuated by an operator to start and stop the motor.

[0093] The power module assembly includes a motor contactor switch (not shown) configured to connect and disconnect electrical power to the motor via a motor power cord 84 extending from the power module assembly to the motor. The contactor switch opens and closes in response to electrical signals from the switch box assembly. When an operator actuates the switch(es) on the switch box to start the motor, the switch box transmits a signal to the power module assembly which causes the motor contactor to close and thereby connect electrical power to the motor. Conversely, when an operator actuates the switch(es) on the switch box to stop the motor, the switch box transmits a signal to the power module assembly which causes the motor contactor to open and thereby disconnect electrical power to the motor. It will be appreciated by those of skill in the art that, as an alternative to the switch box and / or the contactor switch, the motor can be controlled by an operator using a wide variety of components, circuits, and assemblies which are well-known and widely available. Therefore, any one or more of such alternatives may be used within the scope of this disclosure.

[0094] T o use band saw 10, an operator first starts the motor by actuating the appropriate switch(es) on the switch box. Next, the operator positions a workpiece on the table in front of the blade. Depending on the type of cut to be made, the operator may control the position of the workpiece using the fence assembly, a miter gauge assembly (not shown), or the operator may manually control the position of the workpiece to make a “free-hand” cut. In any event, once the workpiece is positioned as desired relative to the blade, the operator begins sliding the workpiece over the table and into contact with the moving blade. The operator continues moving the workpiece past the blade until the desired length of cut is achieved.

[0095] Although moving a workpiece into contact with the moving blade will cause the blade to cut the workpiece, the quality of the cut and the ease with which the cut is made can depend on a variety of factors. Since the band saw blade must move in a loop around the upper and lower wheels, it will be understood that the blade must be somewhat flexible. Nevertheless, it is important for the blade to move in a straight line and without twisting as it passes through the workpiece. The workpiece will typically exert some amount of lateral force on the blade as the operator pushes it into contact and past the blade. Therefore, it is usually desirable to not only ensure proper blade tension, but to also provide structural support to the blade adjacent the workpiece even while the blade is moving. Thus, as shown in Fig. 8, exemplary band saw 10 includes an upper blade guide assembly 86 positioned above the table, and a lower blade guideassembly 88 positioned below the table. The upper and lower blade guide assemblies are configured to support the blade against lateral movement or deflection.

[0096] As best seen in Fig. 9, upper blade guide assembly 86 is mounted to an elevation assembly 90 that includes a vertical support tube 92 attached to linear gear rack components 94. The support tube and gear rack components are received into a gear box (not shown) mounted inside the upper cabinet section. The elevation assembly also includes a handwheel 96 with which an operator can drive the gear box to raise and lower the support tube and gear rack components. Since the upper blade guide assembly is mounted to the bottom of the support tube, an operator can adjust the vertical position of the upper blade guide assembly by rotating the handwheel. Typically, an operator adjusts the vertical position of the upper blade guide assembly to be slightly higher than the height of the workpiece to be cut. This allows clearance for the workpiece to be moved across the table without striking the blade guide assembly, while maintaining the support provided by the blade guide assembly as close to the workpiece as possible. During cutting operations, the workpiece only contacts that section of the blade between the upper blade guide assembly and the top surface of the table. Therefore, that section of the blade is also referred to herein as the “active” section of the blade.

[0097] As shown in Figs. 10-12, upper blade guide assembly 86 includes a guide block positioning assembly 98 with a generally cylindrical tube insert 100. One end of the tube insert is attached to a tube mounting block 102, while the opposite end is received into the bottom of support tube 92. A screw 104 (shown in Fig. 9) threads through the rear wall of the support tube to engage and retain the tube insert within the tube. The cylindrical shape of the tube insert allows the guide block positioning assembly to be rotated relative to the support tube and thereby align the upper blade guide assembly relative to the blade.

[0098] A guide mounting block 106 is mounted to the guide block positioning assembly by an extension post 108. One end of the extension post is received and retained in a matching cavity in the back of the guide mounting block, while the other end passes through a matching hole through the tube mounting block. The front-to-back position of the guide mounting block relative to the blade can be adjusted by sliding the extension post in an axial direction within the tube mounting block. Once the guide mounting block is positioned as desired, the extension post can be secured by a knob and screw assembly 110 which threads into the tube mounting block to press against the extension post.

[0099] The exemplary upper blade guide assembly includes four rotatable side blade guide members 112, and one rotatable rear blade guide member 114. The exemplary guide members are in the form of standard ball bearings with inner and outer bearing races which rotaterelative to each other about a common axis. In alternative embodiments, one or more of the guide members may take different forms such as stationary or static guide pads made of ceramic, plastic, metal, wood, or etc. Additionally, fewer or more guide members may be used. In any event, the guide members are all supported by the guide mounting block such that the positions of the guide members may be adjusted relative to the guide mounting block and the blade.

[0100] Rear guide member 114 is mounted on a bushing 116 which is inserted into the inner race of the side guide member. The bushing is attached to an extension post 118 by a screw 120. The extension post is slidably inserted through a matching hole in the guide mounting block and secured by a knob and screw assembly 122. As a result, the position of the rear guide member relative to the guide mounting block can be adjusted in a direction along the axis of the extension post. This allows the front-to-back position of the rear guide member relative to the blade to be adjusted independent of the guide mounting block. Typically, the rear guide member is positioned so that the outer race is closely spaced from, or just touching, the rear edge of the blade. Thus, the outer race provides support to the rear of the blade against deflection or movement of the blade in a backward direction (relative to the front of the band saw). Since the outer race of the rear guide member is rotatable relative to the inner race, the outer race can rotate when in contact with the moving blade.

[0101] The side guide members are mounted on a pair of mounting posts which pass through the inner races of the side guide members. Two side guide members are mounted on each post and are retained on the posts between a flange region 126 and retaining rings 128 which are installed in slots formed on the mounting posts. A bolt and washer assembly 130 passes through the center of each mounted post and threads into threaded holes 132 formed in one end of axle components 134. The opposite ends of the axle components are inserted into holes 136 in guide mounting block 106. The front-to-back position of the mounting posts and side guide members is not adjustable relative to the mounting block. Therefore, the front to back position of the side guide members relative to the blade are adjusted by adjusting the front-to-back position of the guide mounting block. Once the front-to-back position of the guide mounting block and side guide members is adjusted as desired, the front-to-back position of the rear guide member can be adjusted as needed without moving the side guide members.

[0102] While the rear guide member provides support to the blade against rearward deflection, the side guide members support the blade against side-to-side or left and right deflection. The upper blade guide assembly is positioned so that one mounting post, along with the side guide members mounted thereon, are positioned on either side of the blade. Thus, the side guide members positioned to the left side of the blade (also referred to herein as the “leftguide members”) provide support to the blade against leftward deflection, while the side guide members positioned to the right of the blade (also referred to herein as the “right guide members”) provide support to the blade against rightward deflection.

[0103] The side-to-side positions of the left and right guide members are adjustable relative to the blade due to the eccentric alignment of the guide posts to the axle components. In addition, since each guide post is attached to a different axle component, the side-to-side positions of the left and right guide members are adjustable independent of each other. The eccentric positions of the mounting posts relative to the axle components are best seen in the cross-sectional view of Fig. 11. As shown by the dashed-line axes, threaded hole 132 is formed parallel to, but spaced-apart from, the center cylindrical axis of the axle component. As a result, when the axle component is rotated relative to the guide mounting block, the mounting posts and side guide members move in a circle or orbit around the axis of the axle component. The range of side-to-side adjustment will depend on the distance between the axis of the axle component and the axis of the mounting post. In the exemplary embodiment, the axes are spaced apart by approximately 2.5mm which allows a side-to-side adjustment of approximately + / - 2.5mm from a central position, or a total of 5mm from a position of maximum leftward adjustment to a position of maximum rightward adjustment.

[0104] As best seen in Fig 12, when an axle component is inserted into a hole 136, a spring ball retention assembly 138 engages a concavity or groove 140 formed in the axle component to retain the axle component in the hole. Each spring ball retention assembly includes a small ball 142, a spring 144, and a screw 146. The ball and spring are inserted into holes 148 formed in both sides of the mounting block and retained in the holes by screws 146 which thread into the holes. The balls are pressed into grooves 140 by the springs so as to restrain axial movement of the axle component. However, the engagement of the balls in the grooves does not prevent an operator from inserting or removing the axle components from the hole. An operator can insert or remove the axle components by hand and without the use of tools by pressing or pulling the axle component with moderate force sufficient to move the spring balls over the grooves. The amount of force required can be adjusted by threading or unthreading screw 146 to adjust the compression of spring 144.

[0105] Likewise, the engagement of the balls in the grooves does not prevent rotational movement of the axle components. Thus, an operator can rotate the axle components by hand. A pair of o-rings 150 are installed on the axle components on either side of grooves 140. The o- rings are formed of a resilient material such as rubber so as to slightly deform when the axle components are inserted in holes 136. The o-rings press against the inner bore of holes 136 andcreate a relatively tight fit between the holes and the axle components. This fit adds a moderate amount of frictional bias to prevent unintended rotation of the axle components. The o-rings also prevent any slight pivoting movement of the mounting posts and side guide members within the holes which might otherwise occur due to manufacturing tolerances and resulting clearances between the axle components and holes.

[0106] Each mounting post includes a knob region 152 with which an operator can rotate the mounting post and attached axle component. As the mounting post is rotated, the eccentricity of the mounting post relative to the axle component causes the corresponding side guide members to move in an orbit around the axis of the axle component. Thus, the operator can adjust the side-to-side position of the side guide members by rotating the corresponding mounting post. Typically, an operator will adjust the position of the side guide members so that the guide members are slightly spaced from, or just touching, the adjacent side of the blade.

[0107] As noted above, the contact between o-rings 150 and the inner bores of holes 136 will provide some friction to help prevent the axle components from accidentally rotating away from a position set by an operator due to vibration, the force of the blade pushing against the guide, and other minor incidental forces. In addition, the axle components include detent features 154 in the form of a ring of raised ridges or ribs which are engaged by spring ball detent assemblies 156. Each spring ball detent assembly includes a ball 158, a spring 160 and a screw 162. The spring ball detent assemblies are installed in holes 164 formed in a guide shield 166, which is attached to the guide mounting block by screws 168. The balls and springs are held within holes 164 by screws 162 which thread into the holes. The balls are pressed against ribbed detent rings 154 by springs 160. As the mounting posts are rotated by an operator, the balls roll across the ribs and intervening valleys thereby creating a tactile impulse, stimulus, or perceptible detent to the operator for each rib and valley pair that pass by the ball.

[0108] In the exemplary embodiment, detent rings 154 include 75 rib / valley pairs evenly spaced around the axle component. Thus, one complete (360 degree) rotation of a mounting post will generate 75 tactile signals or vibrations from the interaction between the spring ball detent assembly and the ribbed detent ring. This tactile signal will be perceived by an operator through the knob region of a mounting post. Thus, the spring ball assemblies may also be thought of as detent mechanisms which provide tactile stimuli or feedback to an operator who rotates the knob portion of a mounting post. Each tactile stimuli indicates the position of the guide member has been adjusted by one increment as defined by the rib / valley pairs.

[0109] Additionally, the force exerted by spring 160 on ball 158 helps to prevent accidental rotation of the axle component. Since rotation of the axle component causes the ball to be movedaway from the axis of the axle component as the ball passes over a rib, the ball must move against the force of the spring. Thus, a non-zero amount of torque must be applied to the mounting post to overcome the force of the spring on the ball. In other words, the detent engagement between the ribbed ring and the detent spring ball assembly allows for tool-free adjustment of the position of the side guide members. An operator simply rotates the mounting post by applying sufficient torque to overcome the force of the spring on the ball. Once the side guide member is positioned as desired, it is essentially locked against accidental repositioning caused by normal operation of the band saw. That is, the position of the side guide members will only change when torque is applied to rotate the mounting posts around their axes.

[0110] From the above discussion, it will be recognized that the side guide members are eccentrically attached or mounted to the guide mounting block. The mounting posts and axle components, along with the associated o-rings and hardware described above, may be understood as forming eccentric attachment mechanisms for attaching the guide members to the mounting block such that the positions of the guide members relative to the mounting block can be adjusted by an operator. The positions of opposing guide members can be adjusted independently and without the use of tools. Likewise, an operator may attach or detach the attachment mechanisms (and corresponding guide members) to and from the mounting block both independently and without the use of tools.

[0111] Turning attention now to Figs. 13-14, it can be seen that the configuration of lower blade guide assembly 88 is similar to that of the upper blade guide assembly. The lower guide assembly is mounted to band saw 10 by a mounting bracket 168 with a shaft 170 extending outward from the back of the bracket. The shaft is configured to insert into a channel 172 (shown in Fig. 3) formed in trunnion block 32. A lower guide mounting block 174 is attached to the mounting bracket by screws (not shown). A rear guide member 114 is mounted to the mounting block by an extension post 118 which attaches to a bushing that passes through the bore of the rear guide inner race. The front-to-back position of the rear guide member is adjustable, relative to the mounting block, by sliding the extension post forward or backward through an opening in the mounting block and then securing with a knob and screw assembly 122. Since the lower blade guide assembly is positioned just below the bottom surface of table 26, it is not necessary to adjust the vertical position of the lower blade guide assembly.

[0112] The side guide members 112 of the lower guide assembly are installed on mounting posts 124 by retaining rings 138, and the mounting posts are attached to axle components 134 by bolt and washer assemblies 130. The axle components are inserted into holes 136 in the mounting block and retained by spring ball retention assemblies 138 whichengage grooves formed in the axle components. In place of guide shield 166, the lower guide assembly includes a housing assembly 174 which includes a housing base 176 that is attached to the mounting block by screws 168. The housing assembly also includes a housing cover 178 which pivotally attaches to base 176 so that the cover can pivot from a closed position in which the guide members are substantially enclosed in the housing assembly, to an open position in which the guide members are exposed (such as shown in Fig. 13). Spring ball detent assemblies are inserted into channels formed in the housing base so as to engage the ribbed detent rings 154 on the axle components. The side-to-side positioning of the side guide members in the lower guide assembly is identical to that of the upper guide assembly. Likewise, the engagement of the spring ball detent assemblies with the detent rings on the axle components is similar on both the upper and lower guide assemblies.

[0113] Those of skill in the art will appreciate that the detent engagement mechanisms described above can be modified in various ways for either one or both of the upper and lower guide assemblies. For example, the detent rings may have a different number of ribs or may have different detent structures than ribs, and / or may be formed in different locations on the axle components. Alternatively, or additionally, the spring ball detent assembly may be replaced with flexible structures formed in the guide shield which engage the detent structures on the axle components. As a further alternative, screws 162 and springs 160 may be replaced by a resilient material between the guide shield and balls 158 to urge the ball into engagement with the ribbed detent ring. As another alternative, the guide shield may be formed with structures to hold the balls and flexibly urge them into contact with the detent structures on the axle components. Furthermore, the detent structures may be formed on the guide shield and / or housing base and the detent engagement mechanisms may be part of, or mounted to, the axle components. These are just a few illustrations of the alternative embodiments of detent structures and detent engagement mechanisms which are possible within the scope of this disclosure.

[0114] In addition to supporting the blade against lateral deflection, a good quality cut often requires providing support to guide the workpiece in a straight line as it contacts the blade. One mechanism for guiding a workpiece is known as a rip fence. Typically, a rip fence is used when an operator is making a cut along the length of a workpiece, though other operations are also possible using a rip fence. In any case, a rip fence provides a workpiece alignment and support surface (also referred to herein as a “guide surface”) that is substantially parallel to the side of the blade. An operator uses a rip fence by first positioning the fence so that the guide surface is spaced apart from the blade by the desired cut width. Next, the operator places the workpiece on the table and positions it against the guide surface and in front of the blade. Finally,the operator begins sliding the workpiece across the table and along the guide surface until the workpiece contacts the blade. The operator continues to slide the workpiece along the guide surface until the desired cut length is achieved.

[0115] As shown in Figs. 15-16, exemplary fence assembly 50 includes three subassemblies: a carriage assembly 200, a positioning plate assembly 202 adjustably mounted to the carriage assembly, and a workpiece guide assembly 204 that is adjustably mounted to the positioning plate assembly. Carriage assembly 200 is configured to engage and slide along rail 48, thereby moving workpiece guide assembly 204 laterally toward or away from the blade. Positioning plate assembly 202 enables the position and orientation of the workpiece guide assembly to be adjusted relative to the carriage assembly. As a result, the position and orientation of the guide surface relative to the blade can be fine-tuned to achieve the desired cut. Each subassembly is described in more detail below.

[0116] Referring now also to Figs. 17-18, the exemplary workpiece guide assembly includes an elongate aluminum extrusion frame 206 with a generally L-shaped profile, though other shapes and materials may be used. Assembly 204 also includes an elongate faceplate 208 that is removably mounted to frame 206 with a plurality of screws 210. The threads of screws 210 engage threaded inserts (not shown) mounted in the back side of the faceplate, while the heads of screws 210 fit into keyhole slots 212 in the frame. The guide assembly also includes four glide pads 214 adhered to the bottom corners of the frame, as well as end caps 216 which cover openings on each end of the extruded frame. Channels 218 are formed in the bottom or underside of the frame to engage mating structures on the positioning plate assembly, as will be described in more detail below.

[0117] The front side of faceplate 208 (i.e., opposite the frame) is substantially flat and forms a guide surface 220 against which an operator can position and slide a workpiece. The guide surface is generally rectangular in shape and includes an elongate, generally horizontal axis 222 (indicated by dash lines in Fig. 15), as well as a generally vertical axis 224 (also indicated by dash lines in Fig. 15). It should be understood that horizontal axis 222 and vertical axis 224 are referenced to the top surface of table 26. Thus, when the table is in a horizontal position (relative to the ground supporting the band saw), the vertical axis will also be vertical with reference to the ground. However, when the table is tilted from horizontal, the rail and fence assembly will be likewise tilted so that the vertical axis remains vertical or perpendicular with reference to the table top but is no longer vertical with reference to the ground.

[0118] For most cutting operations using a rip fence such as exemplary fence 50, it is desirable for horizontal axis 222 to be substantially parallel to the left and right sides of the activesection of blade 70. In contrast, it is desirable for vertical axis 224 of the guide surface to be substantially perpendicular to the top surface of table 26. Since the table can be tilted relative to the cabinet and the active section of the blade, and since the rail and fence assembly tilt with the table, the angle of vertical axis 224 relative to the sides of the active section of the blade will be the complement of the angle between the top surface of the table and the vertical axis of the active section of the blade. To ensure the axes of guide surface 220 are properly positioned and aligned relative to the blade, fence assembly 50 includes several mechanisms for adjusting the position and orientation of the workpiece guide assembly and guide surface.

[0119] To adjust the width of cut, an operator moves the guide surface closer to, or further from, the side of the active portion of the blade by sliding the carriage assembly along the rail. As shown in Figs. 19-20, the exemplary carriage assembly includes a carrier base 230 with a generally U-shaped profile sized to fit over the top of the rail and extend at least partially down the front and rear sides of the rail. The exemplary carrier base is formed of stamped sheet steel, though other well-known materials and manufacturing methods are possible. Glide pads 232 are attached to the inner sides of each end of the carrier base to contact and slide along the sides of the rail. The front and rear sides of the carrier base are spaced apart such that the distance between the front and rear glide pads is slightly larger than the front-to-back width of the rail. The exemplary glide pads are formed of a plastic material to provide a low-friction interface between the carrier base and sides of the rail and to enable the carrier base to slide along the rail with relatively little lateral force and without scratching or mauling the rail.

[0120] Plastic leveling set screws 234 are threaded into holes on the top of each end of the carrier base so as to protrude through the top of the carrier base and rest on the top of the rail. By adjusting the relative vertical positions of the leveling screws in the carrier base, an operator can adjust the angle at which the carrier base rests on the rail. This enables the operator to ensure vertical axis 224 of the guide surface is perpendicular to the top surface of table 26. The leveling screws also provide a low-friction interface between the carrier base and the top of the rail. Since the carrier base is separated from the rail by the glide pads and the leveling screws, an operator can slide the carrier base smoothly along the length of the rail without lifting it from the rail. In addition, the shape of the carrier base and the positions of the glide pads and leveling screws maintain the relative alignment between the fence assembly and the rail as the fence assembly slides along the rail.

[0121] Once the carrier base has been moved to its desired position, it is frictionally locked in place by engaging a locking pawl 236. The locking pawl is pivotally mounted by bolt 238 to a cam mounting bracket 240 that is welded to the carrier base. A locking handle 242 is attached tothe end of the pawl opposite the rail to allow an operator to engage and disengage the pawl by raising and lowering, respectively, the locking handle. A contact pad 244, constructed from urethane or a similar material, is attached to a flexible bracket (not shown) which is mounted to the underside of the carrier base so as to position the contact pad between the pawl and the rail. The flexible bracket is formed to bias the contact pad away from the rail when the locking handle is in the up or unlocked position. When the handle is lowered to the locked position, the cam pushes against the flexible bracket to move the contact pad into contact with the front of the rail. This action pulls the carrier base slightly forward until the rear glide pads press against the rear of the rail. Thus, the squeezing force between the contact pad and the rear glide pads against the front and rear sides of the rail functions to clamp the carrier base to the rail.

[0122] In summary, when using rip fence assembly 50, an operator raises locking handle 242 to the unlocked position, thereby unclamping carrier base 230 from the rail, and then slides the carrier base along the rail until the desired width of cut is reached, at which point the operator lowers the locking handle to the locked position, which clamps the carrier base in the new position. An indicator lens 246 is mounted to the carrier base and hovers over a scale or ruler (not shown) located on the top surface of the rail. The indicator lens includes an indicator line and the position of the indicator line over the ruler displays to an operator the approximate width of cut for the current fence position.

[0123] In addition to moving the guide surface left and right across table 26, it is sometimes desirable to move the guide surface forward and backward across the table. For example, when making a longitudinal cut through a long workpiece, an operator may want to move the guide surface forward of the blade to increase the length of the guide surface which can contact the workpiece prior to starting the cut and during the initial portion of the cut. To enable this front-to-back adjustment of the guide surface, the position of the workpiece guide assembly in the exemplary embodiment can be moved forward and backward relative to the positioning plate assembly.

[0124] Focusing now on Figs. 17-18 and Figs. 21-23, positioning plate assembly 202 includes a positioning plate 250 which is formed with an elongate rib 252 which extends along the top of the positioning plate in a generally forward and backward direction when fence assembly 50 is mounted on rail 48. Rib 252 is shaped to engage channels 218 on the underside of frame 206. When the frame is mounted on the positioning plate so that the rib fits into one of the channels, horizontal axis 222 is aligned to be generally parallel to the rib.

[0125] As best seen in Figs. 17 and 23, one channel is formed on the underside of the frame near the faceplate, while the other channel is formed on the underside of the frame oppositethe faceplate. When the frame is positioned on the positioning plate so that the rib fits within the channel near the faceplate, the guide surface faces toward the right side of the band saw (as shown in Fig. 15). However, the frame can be flipped so that the rib fits within the channel opposite the face plate. In this orientation (not shown) the guide surface faces toward the left of the band saw. Thus, an operator can select the orientation of the frame on the positioning plate so that the fence can be positioned either on the left or right of the blade while still allowing the guide surface to guide the workpiece.

[0126] The height of exemplary faceplate 208 is approximately 5.5 inches which provides good support for workpieces of various heights. However, when making relatively narrow cuts where the faceplate is positioned relatively close to the blade, the upper blade guide assembly must be raised above the top of the faceplate to avoid interference. Thus, if an operator wishes to make a narrow cut on a relatively thin workpiece (i.e., substantially less than 5.5 inches), it would not be possible to lower the blade guide close to the top of the workpiece to provide maximum support to the blade to prevent lateral deflection. For such operations, the operator can flip the workpiece guide assembly around so that the opposite channel fits on the rib. In this orientation of the workpiece guide assembly (not shown), the face plate would face away from the blade. Instead, an auxiliary and shorter guide surface 254 formed into frame 206 would face the blade and can be used to guide the workpiece. The height of exemplary short guide surface 254 is approximately 0.5 inches, thereby allowing the upper blade guide assembly to be lowered to a position just above even a relatively thin workpiece.

[0127] The positioning plate assembly includes a clamp block 256 which is selectively movable by an operator to alternately clamp and release the workpiece guide assembly to the positioning plate assembly. This clamp mechanism allows allow an operator to easily adjust the front-to-back position of the guide surfaces and to flip the orientation of the workpiece guide assembly, while also holding the workpiece guide assembly in secure alignment with the blade after such adjustments are made. The clamp block is shaped to fit within a clamping channel 258 formed in the extruded frame. The clamp block includes shoulders 260 along two opposing sides which engage matching shelves 262 formed in the clamping channel. When the frame is resting on the positioning plate, one channel 218 fits over rib 252 while the bottom surface of the frame opposite that channel rests on a ledge 264 formed on the positioning plate. The ledge is formed so that when the frame is installed on the positioning plate, the rib and ledge orient the frame so that vertical axis 224 is generally perpendicular to the top surface of the rail. As discussed above, the perpendicularity of the vertical axis relative to the top surface of the table can be finely adjusted by leveling screws 234. The end of the frame which extends over the table is supported by contactbetween the table top and pads 214 so that horizontal axis 222 is generally parallel to the top surface of the table.

[0128] When downward force is applied to clamp block 256, shoulders 260 apply downward force on shelves 262, thereby pressing the frame against the positioning plate. With sufficient downward force on the clamp block, the frame will be clamped to the positioning plate by friction between the frame and positioning plate. In this clamped state, the frame is held tightly to the positioning plate and will not move relative to the positioning plate under normal operating loads. Conversely, when downward force on the clamp block is removed, then the frame is no longer clamped against the positioning plate and is free to slide in a direction parallel to horizontal axis 222 when an operator applies moderate forward or backward force.

[0129] Downward force on the clamp block is provided by a clamp bolt 266. The shank of bolt 266 passes through holes in both the clamp block and the positioning plate. The hex head of the bolt is retained in a 12-sided socket 268 formed in the top of the clamp block, which prevents the bolt from rotating relative to the clamp block. The threaded end of the clamp bolt is threaded into the bore of a cam nut 270 below the positioning plate. A compression spring 272 is positioned around the end of the clamp bolt that extends below the cam nut. The top of the spring presses against the bottom of the cam nut, while the bottom of the spring presses against the top of carrier base 230, thereby biasing the cam nut upward.

[0130] The top portion of cam nut 270 is formed as a short cylinder with a cam top surface, while the bottom portion of the cam nut has a square outer profile. The top portion of the cam nut fits into a circular socket 274 formed into the underside of the positioning plate. The upper surface of socket 274 includes cam features configured to interact with the cam surface of the cam nut. When the cam nut is rotated within the socket, the opposing cam features on the positioning plate and cam nut cause the cam nut to move up and down within the socket.

[0131] When the cam nut is rotated within the socket and is pushed downward by the interaction of the cam surfaces, the clamp bolt is pulled downward with the nut. This movement applies downward force on the clamp block to clamp the frame to the positioning plate. Conversely, when the cam nut is rotated within the socket so that the interaction of the cam surfaces allows the cam nut to rise under the biasing of spring 272, the clamp bolt is pushed upward with the nut. This movement removes downward force on the clamp block, thereby unclamping the frame from the positioning plate. In addition, the clamp block is biased upward away from the positioning plate by a pair of compression springs 276. The tops of springs 276 fit within cylindrical sockets formed in the bottom of the clamp block, while the bottoms of the springs rest on the top of the positioning plate. When the clamp bolt moves upward, the clamp block alsomoves upward due to the bias of springs 276. Thus, the frame is alternately clamped and unclamped from the positioning plate by alternately rotating the cam nut between positions at which the cam surfaces and springs cause the cam nut to lower and raise, respectively, relative to the positioning plate.

[0132] To allow an operator to easily rotate the cam nut and clamp or unclamp the frame, the positioning plate assembly includes an arm 278 with a square socket end 280 that fits around the square end of the cam nut. The opposite end of arm 278 includes a handle portion 282 which can be gripped by the operator. The handle portion of the arm is formed of plastic and rests against the top surface of the carrier base. The socket end of the arm fits around the cam nut and rests on an optional washer 284 made of a low friction material such as PTFE. Washer 284 may be interposed between the socket end of the arm and the carrier base to allow the arm to freely pivot against the carrier base. In the exemplary embodiment, the cam surfaces are formed so that a rotation of approximately 45 degrees moves the cam nut between a fully clamped position and a fully unclamped position. Thus, an operator may clamp or unclamp the frame by pivoting arm 278 approximately 45 degrees about the axis of the clamp bolt. Although arm 278 extends outward to the right of the workpiece guide assembly, the location of the arm under both the workpiece guide assembly and the positioning plate ensures that all portions of the arm are beneath the top surface of table 26 when the fence assembly is mounted on the rail. As a result, the arm does not interfere with workpieces sliding across the table regardless of whether the arm is in the clamped or unclamped position.

[0133] To compensate for manufacturing tolerances and to provide a relatively constant downward clamping force, a stack of multiple Belleville washers 286 are positioned beneath the head of clamp bolt 266. The quantity and spring force of the Belleville washers are selected to provide a total possible compression distance comparable to the maximum vertical movement of the cam nut. In addition, the spring force of the Belleville washers is selected to achieve the desired clamping force. To ensure the washer stack is at least partially compressed when the cam nut is at its lowest position, and fully uncompressed when the cam nut is at its highest position, the height of the clamp bolt head relative to the cam nut can be adjusted. This adjustment is made when the cam nut is at its highest position, at which point the clamp block can be pressed down against the urging of springs 276 so that the head of the clamp bolt is above socket 268. Once the bolt head is above the socket, the bolt can be rotated to raise or lower the head relative to the cam nut.

[0134] While clamp bolt 266 retains the clamp block on the positioning plate even when the workpiece guide assembly is completely removed, the bolt does prevent the clamp block fromrotating out of alignment (i.e., alignment to slide into the clamping channel). Therefore, to prevent the clamp block from rotating out of alignment when it is not enclosed in the clamping channel, the positioning plate includes two locating arms 288 which fit into notches 290 on the front and back of the clamp block. The arms prevent the clamp block from rotating about the clamp bolt and also limit the maximum upward travel of the clamp block.

[0135] From the above description, the clamping mechanism for clamping the workpiece guide assembly to the positioning plate should be understood as allowing an operator to pivot an arm in a horizontal plane (i.e., parallel to the top surface of the table) by approximately 45 degrees to apply a force on a portion of the workpiece guide assembly sufficient to clamp the workpiece guide assembly against movement relative to the positioning plate. This clamping force is applied in a direction which is perpendicular to the top surface of the rail. When the carriage assembly is clamped to the rail and the workpiece guide assembly is clamped to the positioning plate assembly, the workpiece guide assembly will be clamped against movement relative to the rail. Conversely, an operator can pivot the arm by approximately 45 degrees in the opposite direction to release the clamping force and unclamp the workpiece guide assembly so as to allow movement of the workpiece guide assembly relative to the positioning plate assembly. However, the positioning plate assembly maintains the lateral and rotational orientation of the workpiece guide assembly relative to the blade by constraining the movement of the workpiece guide assembly to a direction which is generally parallel to horizontal axis 222.

[0136] As noted above, obtaining good quality cuts when using a rip fence usually requires the guide surface to be substantially parallel to the sides of the active portion of the blade. In other words, horizontal axis 222 should be substantially parallel to the side of the blade adjacent the guide surface. Otherwise, the workpiece may be cut at an undetermined angle relative to the side of the workpiece that contacts the guide surface. Since a high degree of parallelism can be difficult to achieve due to manufacturing tolerances, exemplary fence assembly 50 includes an adjustment mechanism that enables an operator to adjust and minimize the angle between horizontal axis 222 and the sides of the blade (hereinafter referred to as the “drift angle”).

[0137] As will be described in more detail below, rail 48 is mounted to table 26 so that the longitudinal axis of the rail is generally perpendicular to the left and right sides of blade 70. Since positioning plate assembly 202 positions the workpiece guide assembly so that guide surface 220 is aligned generally perpendicular to the longitudinal axis of the rail, horizontal axis 222 is generally parallel to the left and right sides of the blade prior to any fine adjustment. Furthermore, the guide surface maintains this general parallelism to the sides of the blade regardless of where the fence assembly is positioned along the rail due to the substantial straightness of the rail.However, if an operator determines that the drift angle is too large, the operator can adjust the drift angle by adjusting the relative angle between carriage assembly 200 and positioning plate assembly 202.

[0138] As shown in Figs. 24-26, the exemplary positioning plate assembly is attached to the carriage assembly by two shoulder bolts 292. The threaded ends of the bolts pass through arcuate openings or slots 294 formed in the bottom of the positioning plate (shown in Fig. 22), and thread into holes 296 on the carrier base (shown in Fig. 16). The heads of the bolts fit into arcuate sockets 298 which are formed in the top of the positioning plate and surround arcuate slots 294. The sides of sockets 298 are inwardly sloped toward the slots. Cone-shaped bushings 300 are installed under the head of each bolt so that the sides of the bushings fit against the sloped sides of the sockets. Plastic glide pads 302 are press-fit into holes 304 (shown in Fig. 22) on the bottom of the positioning plate and extend slightly below the positioning plate to contact the top of the carrier base and provide a smooth sliding interface between the positioning plate and carrier base.

[0139] As best seen in Fig. 25, the lengths of the shoulder bolt shanks and the heights of the bushings are sized so that the positioning plate is held closely against the carrier base without being tightly clamped against the carrier base. However, the wedge-like fit of the bushings within the sockets minimize front-to-back movement or rotation of the positioning plate relative to the carrier base.

[0140] Arcuate slots 294 are concentric with a common center located approximately 200 mm rearward (i.e., toward the rear of the band saw) from the front edge of the table when the fence assembly is mounted on the rail. Since shoulder bolts 292 are free to move along the length of the slots, the positioning plate can slide over the upper surface of the carrier base in an orbit which is concentric with the slots. As a result, the positioning plate can be pivoted about a point or pivot axis that is approximately 200mm rearward of the front edge of table 26. In the exemplary embodiment, the front edge of blade 70 is nominally positioned about 200mm rearward of the front edge of the table. As a result, the exemplary positioning plate pivots about a pivot axis proximate the front of the blade.

[0141] In conventional rip fence assemblies designed for use with a band saw and including a mechanism for adjusting the drift angle, the pivot axis is located forward of the front edge of the table and usually proximate the carriage assembly or rail. This situation is schematically illustrated in Fig. 27, in which conventional fence assembly 310 is mounted to slide on a rail 312, which is attached to a table 314. The conventional fence assembly includes a guide surface 316 that extends over table 314 and past a blade 318. The pivot axis 320 for adjustingthe drift angle of fence assembly 310 is proximate the rail as shown. In the schematic illustration of Fig 27, the guide surface is initially misaligned counter clockwise relative to blade 318. When the drift angle is adjusted to make the guide surface parallel to the sides of blade 318 (as indicated by the outline in dashed lines), the distance between the guide surface and the blade is substantially decreased, thereby substantially decreasing the width of cut.

[0142] As will be appreciated by those of skill in the art, when the drift angle of a guide surface is adjusted, the change in the width of cut will be proportional to the front-to-back distance between the blade and the pivot axis of the drift angle adjustment. For a commonly used band saw with 14 inch diameter wheels, the distance from the blade to the rail is 8 inches or more. In which case, each 1 degree change in the drift angle will result in a change in the cut width of at approximately 0.14 inch or more. Since many band saw operations require a width of cut accuracy of much less than 1 / 8 inch (0.125 inch), such a large change in the width of cut when adjusting the drift angle is undesirable. Indeed, for fence assemblies which allow the drift angle to be adjusted with a pivot point that is proximate the rail, it is often necessary to adjust the indicator lens on the fence assembly which indicates width of cut after the drift angle has been adjusted.

[0143] Turning attention now to Fig. 28, the geometry for adjusting the drift angle on exemplary fence assembly 50 is schematically illustrated. As with the prior example, guide surface 220 is shown as being initially misaligned counter clockwise relative to the sides of blade 70. However, when the drift angle is adjusted (as indicated by the outline in dashed lines), the change in the width of cut is relatively small since the pivot axis 322 of the adjustment is proximate the blade. Although the exact position of the blade will often vary due to several factors including manufacturing tolerances, varying blade tension (which creates varying flex in the internal structure of the band saw), and the position of the blade on the wheels, the drift angle adjustment pivot point for the exemplary embodiment will be a maximum of 1 inch forward or backward of the center of the blade. This results in a maximum change in the width of cut of approximately 0.017 inch per 1 degree of drift angle adjustment.

[0144] While the exemplary drift angle adjustment mechanism described above provides an advantage over prior mechanisms by locating the pivot axis proximate the blade, various modifications and alternatives to the exemplary mechanism are possible within the scope of this disclosure. As just one example, the arcuate slots may be formed in the carrier base and structures may be formed on, or attached to, the positioning plate which slide within the slots to constrain the movement of the positioning plate relative to the carrier base. Furthermore, those of skill in the art will recognize that many other modifications and / or alternatives are possible for constraining the motion of the positioning plate relative to the carrier base to a pivoting motionabout a pivot axis proximate the blade, and that all such modifications and alternatives are within the scope of this disclosure.

[0145] Once the desired adjustment to the drift angle has been completed, further movement of the positioning plate relative to the carrier base is prevented by a drift angle clamp mechanism, which is indicated generally at 324. The drift angle clamp mechanism includes a clamp handle 326 with a cam region 328. The opposing ends of a barrel nut 330 are positioned within bores formed in the cam region of the clamp handle. The shank of a bolt 332 passes through a hole in the center of the barrel nut and the head of the bolt is recessed slightly into the outer surface of the barrel nut. As a result, the head of bolt 332 is captured by the barrel nut within the cam region of the clamp handle. The threaded end of bolt 332 passes through a hole in the center of a clamp plate 334 and is threaded into a nut 336 (best seen in Figs. 16 and 26) which is welded to carrier base 230. As a result, clamp mechanism 324 is attached to carrier base 230 by bolt 332. A wave washer 338 and a spacer bushing 340 are positioned around bolt 332 between the clamp plate and the positioning plate. The wave washer biases the positioning plate forward so that the sides of sockets 298 press against the cone-shaped bushings. This serves to remove hysteresis or play in the positioning plate during adjustment.

[0146] The clamp plate is held between the cam region of clamp handle 326 and the front edge of the positioning plate. The clamp handle is free to pivot around the barrel nut in a generally horizontal plane so that the portion of the cam region that is nearest the front edge of the positioning plate changes as the handle pivots. Furthermore, the thickness of the cam region between the barrel nut and the positioning plate varies as the clamp handle pivots. Since the distance between the barrel nut and the carrier base is fixed by the head of bolt 332, pivoting the clamp handle moves the clamp plate forward or backward relative to the carrier base. When the clamp handle is pivoted clockwise (as viewed from above) the spacing between the cam region and the positioning plate is reduced. Conversely, when the clamp handled is pivoted counterclockwise the spacing is increased.

[0147] Clamp mechanism 324 is initially adjusted by pivoting the clamp handle counterclockwise and threading bolt 332 into welded nut 336 until the spacing between the cam region and the front edge of positioning plate is slightly larger than the thickness of the clamp plate. Thus, when the clamp handle is pivoted counterclockwise to its “unclamped position” as shown in Fig. 29, the clamp plate is not pressed against the positioning plate by the cam region of the clamp handle. As a result, the positioning plate is free to move relative to the carrier base and an operator can adjust the drift angle as described above. However, when the clamp handle is pivoted in a clockwise direction to its “clamped position” as shown in Fig. 30, the clamp plate ispressed against the front edge of the positioning plate by the cam region. This generates forward clamping force on the positioning plate so that bushings 300 are pressed against the sides of slots 298. Consequently, the positioning plate is clamped between the clamp plate and the carrier base and is, therefore, fixed relative to the carrier base. To summarize, an operator adjusts the drift angle by pivoting the clamp handle to its unclamped position, adjusting the position of the positioning plate relative to the carrier base until the desired drift angle is achieved, then pivoting the clamp handle to its clamped position to prevent further movement of the positioning plate relative to the carrier base.

[0148] As discussed above, exemplary fence assembly 50 is configured to mount on, and slide along, rail 48. As shown in Figs. 31-35, rail 48 is pivotally mounted to the front edge of table 26. The rail is pivotal between a substantially horizontal or “operational” position as shown in Fig. 31 , and a generally vertical or “nonoperational” position as shown in Fig. 32. When the rail is in the operational position, the longitudinal axis of the rail is substantially parallel with the front edge of table 26. In the operational position, an operator can mount the rip fence on the rail and then slide the fence along the rail to set the width of cut.

[0149] When the rip fence is removed the rail may be pivoted approximately 100 degrees in a clockwise direction (as viewed from the front of the band saw) to the nonoperational position. In the nonoperational position, the upper end of the rail extends above table 26 and, therefore, would usually interfere with an operator attempting to slide a workpiece across the table. In other words, when the rail is in the nonoperational position, an operator cannot operate the band saw as intended to cut workpieces. Instead, an operator pivots the rail to the nonoperational position to enable a band saw blade to be installed or removed.

[0150] Table 26 includes a narrow U-shaped opening 350 with the rounded end near the center of the table and the open end at the front edge of the table. When the band saw blade is installed on the upper and lower wheels, the active section of the blade passes through the table near the rounded end. During normal operation, table insert 46 is mounted on the table so as to substantially fill opening 350, except for a small slot 352 through which the blade passes. The top surface of the table insert is adjustably positioned to be relatively flush with the top surface of the table. The table insert prevents workpieces or other objects from falling through opening 350, and also provides vertical support for workpieces in the area around the blade.

[0151] Since the open end of opening 350 is at the front edge of the table, and since the blade is a continuous loop, a portion of the blade must pass through the front edge of the table during installation or removal. Thus, to install or remove a blade on the band saw, an operator first pivots rail 48 to the nonoperational position and lifts the table insert off the table. At this pointthe rail no longer extends past opening 350, and the blade may be moved freely into and out of the opening in the table.

[0152] To enable an operator to pivot the rail quickly and easily between the operational and nonoperational positions, the rail is attached to table 26 by a single pivot connection mechanism 354. The pivot connection mechanism is mounted to the front edge of the table and to the right of opening 350. When the rail is in the operational position, the end of the rail that extends to the left of opening 350 is supported by a bracket assembly 356 that is mounted to the left front edge of the table. However, the rail is not mechanically fastened to the bracket assembly. As a result, an operator can raise the left side of the rail off the bracket assembly and toward the nonoperational position without tools and without disengaging any mechanical fasteners. To return the rail to its operational position, an operator can pivot the upper end of the rail downward until it rests on the bracket assembly.

[0153] Exemplary pivot connection mechanism 354 includes a L-shaped pivot bracket 358. One end of the pivot bracket is fastened to the bottom of the rail by screws 360. The opposite end of the pivot bracket is fastened to a pivot bushing 362 by a screw 364. As best seen in Fig. 34, pivot bushing 362 is positioned within a horizontal bore formed in table 26. A set screw 366 is threaded into the rear end of the pivot bushing, and a lock nut 368 retains a flat washer 370 proximate the rear end of the pivot bushing. Therefore, the pivot bushing is able to rotate but is constrained against axial movement within the bore formed in the table. A first Belleville washer 372 is disposed on the front end of the pivot bushing between the table and the pivot bracket, while a second Belleville washer 374 is disposed on the set screw between the lock nut and the flat washer. The Belleville washers serve to generate opposing axial biases to the pivot bushing to reduce any axial movement or play while allowing the pivot bushing to freely rotate. Additionally, a pair of o-rings 376 are disposed within a pair of grooves 378 formed in the outer surface of the pivot bushing. The o-rings fit within the bore formed in the table and provide a resilient interface between the pivot bushing and the bore so that the pivot bushing rotates smoothly within the bore.

[0154] Bracket assembly 356 includes an L-shaped support bracket 380 which is fastened to the front edge of the table by screws 382. A cover 384 is attached to the support bracket by screws 386. The exemplary cover is formed of plastic and shaped to include a recess or channel 388 sized to receive the left end of rail 48 when the rail is in the operational position. Thus, the cover serves to protect the surface of rail 48 from scratches while supporting the rail in a generally horizontal position. As noted above, the rail is not mechanically fastened to bracket assembly 356. However, the bracket assembly includes a magnet 390 positioned on the horizontal end ofsupport bracket 380 and beneath cover 384. Since exemplary rail 48 is formed of steel tube, when the rail is in the operational position, magnet 390 exerts a non-contact, downward retention force on the rail to hold the rail in position. This non-contact, remotely generated retention force, in addition to normal gravitational force, helps to ensure the rail does not accidentally pivot away from the operational position due to inadvertent torque applied to the rail by an operator. However, the retention force is not so strong as to prevent an operator from pivoting the tube to the non- operational position.

[0155] In addition to enabling the rail to pivot relative to the table, pivot bushing 362 also functions to engage and disengage an alignment mechanism, indicated generally at 400 in Fig. 35. As a consequence of the relatively long distance that hole 350 extends past the front edge of the table, the top surface of the table near the front edge can become misaligned due to residual stress in the cast iron, differing forces on the table, etc. Therefore, to ensure the table top surface is substantially horizontal and coplanar across opening 350 during operation of the band saw, table alignment mechanism 400 provides a link between the front edges of the table on either side of opening 350 which operates to hold the top surfaces in alignment.

[0156] Focusing now on Figs. 34-38, table alignment mechanism 400 includes an alignment rod or crossbar 402, one end of which is pivotally connected to one end of a first link 404 by a spring pin 406. The opposite end of link 404 is attached to slide within the U-shaped channel of a second link 408. A pair of spring pins 410 are press-fit into holes in link 404 so as to slide within slots 412 formed in link 408. Spring pins 410 constrain the relative movement between links 404 and 404 to a single direction, while the length of slots 412 limit the range of relative travel between the two links. A compression spring 414 is positioned over the center of link 404 and is constrained on one end by link 408, and on the other end by shoulders 416 formed on link 404. The spring length is selected so that the spring remains in some degree of compression throughout the range of travel between the two links. As will be described in more detail below, spring 414 functions to prevent the rail from dropping quickly onto support bracket assembly 356.

[0157] The end of link 408 which is opposite slots 412 is pivotally connected to a pivot arm component 418 by a spring pin 420. The pivot arm component includes a generally cylindrical bore 422 which is configured to fit over the generally cylindrical outer surface of pivot bushing 362. In addition, the pivot arm component is rotationally keyed or coupled to pivot bushing 362 by flat faces 424 on bore 422 which engage corresponding flat faces 426 on the outer surface of the pivot bushing. Furthermore, as best seen in the magnified circles of Fig. 35, pivot bracket 358 includes a generally rectangular opening 428 which fits over a rectangular end 430 of the pivot bushing so that the pivot bracket is rotationally keyed to the pivot bushing. As a result, the pivotarm component is also rotationally keyed to the pivot bracket Thus, when the rail is pivoted by an operator, the rotation of pivot bracket 358 causes an identical rotation of pivot arm component 418. In other words, by pivoting the rail from its nonoperational position to its operational position, an operator simultaneously rotates the pivot arm component approximately 100 degrees in a counterclockwise direction as viewed from the front of the band saw. Conversely, by pivoting the rail from its operational position to its nonoperational position, an operator simultaneously rotates the pivot arm component approximately 100 degrees in a clockwise direction.

[0158] Link 408 is connected to an arm 432 on pivot arm component 418 that extends radially outward from bore 422. When the rail is in its operational position, arm 432 extends from the bore in a direction toward link 404, as illustrated in Fig. 37. Conversely, when the rail is in its nonoperational position, arm 432 extends generally upward and slightly away from link 404, as illustrated in Fig. 38. As a result, link 408 is pushed in a direction toward link 404 when the rail is pivoted to its operational position but pulled in a direction away from link 404 when the rail is pivoted to its nonoperational position. Thus, pivot arm component 418 functions as a cam to convert the rotational motion of the pivot bushing to translational motion of link 408. The maximum rotation of the pivot arm, and therefore, the maximum translation of link 408, is limited by a spring pin 434 mounted in table 26 which contacts arm 432 once the pivot arm component has rotated approximately 100 degrees. This engagement between spring pin 434 and arm 432 also limits the maximum pivot of rail 48. While the location of spring pin 434 in the exemplary embodiment was selected to allow approximately 100 degrees of rotation so that the rail could be pivoted past vertical and, thereby, remain stable in its nonoperational position, alternative embodiments may be configured to allow more or less rotation.

[0159] As best seen in Fig. 37, when the rail is pivoted to its operational position and the pivot arm component pushes link 408 toward link 404, spring pins 410 reach the end of slot 412, at which point link 404 is pushed toward opening 350. Consequently, link 404 pushes crossbar 402 toward opening 350 until the crossbar extends completely across the opening. The bottom of table 26 includes alignment channels 436 on either side of the opening. When the rail is in its operational position, the crossbar is positioned within the alignment channels on both sides of the opening. The channels are sized to allow the crossbar to slide without excess clearance. As a result, when the crossbar is positioned within the channels on both sides of the opening, the crossbar functions to align the channels along a common horizontal axis. This causes the table top surface on either side of opening 350 to be aligned in a common horizontal plane. In summary, when the rail is in its operational position the crossbar extends across opening 350 to align the top surface of the table, on both sides of the opening, to a common or shared plane.

[0160] In contrast, when the rail is pivoted to its nonoperational position and the pivot arm component pulls link 408 in a direction away from link 404, spring pins 410 reach the opposite end of slot 412, at which point link 404 is pulled away from opening 350. Consequently, link 404 pulls crossbar 402 away from opening 350 until the crossbar substantially clears the opening, as illustrated in Fig. 38. This allows an operator to move a blade into and out of the opening without interference from the crossbar. In other words, when the rail is pivoted to its nonoperational position, the crossbar is retracted from the opening to allow a band saw blade to be removed or installed. Thus, the crossbar can be thought of as being movable between a first, or “extended,” or “alignment” position in which it extends across opening 350 so as to align the top surface of the table, and a second or “retracted” position in which the crossbar sufficiently clears the opening so as to allow the passage of a blade into and out of the opening. In the alignment position, the crossbar engages the table on both sides of opening 350, while in the retracted position, the crossbar engages the table on only one side of the opening.

[0161] As discussed above, compression spring 414 is compressed between links 404 and 408 to generate a force tending to push the two links apart, and thereby to rotate the arm of the pivot arm component upward. This generates a torque on the pivot bushing tending to pivot the rail upward towards its nonoperational position. In the exemplary embodiment, the spring is selected to generate a force which is sufficient only to partially counteract the weight of the rail as it pivots downward toward its operational position. The force generated by the spring, along with the friction generated by o-rings 376, prevents the rail from dropping quickly onto bracket assembly 356 and possibly causing deformation or damage to the rail. However, once the rail has reached its operational position, arm 432 has rotated about the pivot bushing until it is positioned substantially inline between the axis of the compression spring and the center of the pivot bushing. As a result, the spring no longer generates significant torque on the pivot bushing. This ensures the compression spring does not tend to pivot the rail up from its operational position.

[0162] From the foregoing description, it will be appreciated that exemplary table alignment mechanism 400 provides a removable coupling across the opening in the table through which a continuous loop band saw blade can be installed and removed. When the coupling is established, it engages and aligns the table on both sides of the opening, consequently blocking the passage of a band saw blade into or out of the opening. Conversely, when the coupling is removed so that it no longer engages the table on both sides of the opening, the blade is no longer blocked from passage into or out of the opening. Moreover, this coupling is automatically removed when the rail is pivoted to its nonoperational position, and then reestablished when the rail is returned to its operational position. In other words, the coupling serves to at least partially blockthe opening when the rail is in its operational position but does not block the opening when the rail is in its nonoperational position. While one exemplary table alignment mechanism has been described, it will be appreciated by those of skill in the art that various modifications and alternatives for releasably coupling and aligning the table on both sides of the opening are possible within the scope of this disclosure.

[0163] As described above, exemplary band saw 10 includes a cabinet with upper and lower sections which are enclosed by upper and lower cabinet doors. With the exception of a relatively small section of the band saw blade, which is exposed to allow materials to be cut, all moving components of the band saw which drive the blade are contained within either the motor housing or the enclosed cabinet. This ensures an operator does not come into contact with these moving components which could cause an injury to the operator. However, when the band saw motor is not on and the interior components are not moving, an operator may need to access the interior of the cabinet to install or remove a blade or to perform maintenance. Thus, the cabinet doors are openable to allow access to the interiors of the upper and lower cabinet sections. Each cabinet section includes a handle assembly 450 which is configured to latch the door closed, but which allows an operator to unlatch and swing the door open when necessary. Fig. 39 shows the lower cabinet section and the lower door handle assembly. Since the door handle assemblies of the upper and lower cabinet sections are identical, only the lower door handle assembly is shown and described.

[0164] T urning attention now to Figs. 40-44, door latch mechanism 450 includes a handle base or receiver assembly 452 which is fastened to the cabinet, and a door latch assembly 454 which is fastened to the door. When the door is in a closed position (i.e. , the right side of the door is in contact with the cabinet), the door latch assembly engages the receiver assembly to hold the door in the closed position. Before opening the door, an operator must first disengage the door latch from the receiver.

[0165] Exemplary handle receiver assembly 452 includes a receiver base 456 which is formed to fit within a cutout 458 in the cabinet. The receiver base is fastened to the cabinet by screws 460 which pass through holes formed in the cabinet and thread into nuts 462 which are pressed into sockets in the receiver base. A switch paddle 464 is pivotally attached to the receiver base by two posts 466 which rotationally fit within hoops 468 formed in the receiver base. A normally-open electronic microswitch 470 is fastened to the receiver base by screw and washer assemblies 472 which thread into holes 474 in the receiver base. The switch paddle is pivotal between a first position that engages the microswitch to electrically close the microswitch, and a second position that does not engage the microswitch, thereby allowing the microswitch to returnto its normally-open condition. As will be discussed in more detail below, microswitch 470 enables electrical detection of when the door handle assembly is latched.

[0166] Exemplary door latch assembly 454 includes a latch base 476 which is fastened to the edge of the door by screws 478 which pass through holes formed in the door and thread into nuts 480 which are pressed into sockets formed in the latch base. A latch bar 482 is pivotally attached to the latch base by a rod 484 which is inserted through holes formed in the latch base. The latch bar is pivotal about the elongate axis of the rod between a first or latched position as shown in Fig. 43, and a second or unlatched position as shown in Fig. 44. A pair of torsion springs 486 are positioned over the opposite ends of the rod and engage both the latch base and latch bar to bias the latch bar toward the latched position. The bias forces of the torsion springs are sufficient to hold the latch bar in the latched position, but not so great as to prevent an operator from manually pivoting the latch bar to the open position.

[0167] As best seen in Fig. 43, when the door is closed and the latch bar is in the latched position, a catch 488 formed on the latch bar engages a shelf 490 formed on the receiver base to retain the door latch assembly against the receiver assembly, thereby holding the door in its closed position against the cabinet. When the catch is engaged on the shelf, the catch presses against switch paddle 464 and pivots the switch paddle to its first position, thereby causing the microswitch to electrically close. Thus, when the door is closed and the latch bar is in the latched position, the microswitch will be closed.

[0168] Conversely, when the door is closed but the latch bar is pivoted by an operator to the unlatched position as shown in Fig. 44, the catch no longer presses against the switch paddle and the switch paddle is free to pivot. A small spring or other biasing mechanism within the microswitch is sufficient to slightly pivot the paddle switch away from the microswitch, and thereby return the microswitch to its normally-open condition. The biasing mechanism in the microswitch is insufficient to overcome the biasing of torsion springs 486 when the door is closed and the latch bar is in the latched position. Thus, when the latch is in the unlatched position, the microswitch is electrically open even though the door is still in its closed position. Likewise, when the door is pivoted open so that the door latch assembly is spaced apart from the handle receiver assembly, the catch cannot press against the paddle switch regardless of whether the latch bar is in the latched or unlatched position. Thus, the microswitch is also electrically open whenever the door is in its open position irrespective of the position of the latch bar.

[0169] Since exemplary door latch mechanism 450 includes an electrical switch which is only closed when the door is latched in its closed position, safety for a band saw operator can be enhanced by disabling the motor whenever the door is not closed and latched. This ensures themotor will not start when one or both of the cabinet doors is open. Additionally, the motor can be turned off if a door is opened while the motor is running. In some embodiments, an electrical motor brake can be used to quickly stop the motor in the event a door is opened while the motor is spinning.

[0170] Those of skill in the art will recognize that many different mechanisms are possible for controlling the motor in response to inputs from the cabinet door microswitches. Many such mechanisms are well-known and used on commercially available band saws. Additional mechanisms are described in U.S. Provisional Patent Application, Serial No. , filed> , the entire disclosure of which is incorporated herein by reference. One exemplary mechanism is shown in Fig. 45 and includes a motor control circuit 500 which is connected to a source of electrical power sufficient to drive a motor 502. The source of electrical power may be a standard electrical outlet such as commonly found in residential and commercial buildings, or may be a stand-alone electrical supply such as a generator, a battery, etc. In any event, the motor control circuit is configured to connect and disconnect electrical power to the motor in response to one or more conditions including operator inputs such as START / STOP switches, sensor inputs such as door switches, software instructions, etc. In the context of exemplary band saw 10, the START / STOP switch and a portion of the motor control circuit are contained within switch box assembly 78.

[0171] In the exemplary embodiment of Fig. 45, door switches 504 are connected to the motor in parallel and supply logic level electrical signals to the motor control circuit to indicate whether or not the door is closed and latched. When both switches are closed, signaling the doors are closed and latched, motor control circuit is configured to enable operation of the motor. If selected other conditions are met to indicate the motor should run (e.g., an operator has switched a motor Start / Stop switch to the Start position), the motor control circuit connects electrical power to drive the motor. Conversely, if one or more of the door switches is open, then the motor control circuit is configured to disconnect electrical power from the motor irrespective of the status of any other conditions. Moreover, even if the motor is initially connected to electrical power and spinning, the motor control circuit will disconnect electrical power in the event at least one of the door switches opens.

[0172] An alternative mechanism for controlling a motor is shown in Fig. 46. In this alternative embodiment a motor control circuit 506 is connected to a source of electrical power similar to the embodiment described above. However, door switches 508 are connected in series between the motor control circuit and motor 510. Thus, electrical power to drive the motor is conducted through the door switches which are suitably rated for the electrical power drawn bythe motor. As a result, both door switches must be closed to establish a path for conducting power from the motor control circuit to the motor. If at least one door switch is open, the path is interrupted and electrical power will not reach the motor, thereby preventing it from starting or causing it to stop if already running.

[0173] The embodiments shown in Figs. 45-46 are just two examples of the many different mechanisms which may be implemented to control the operation of a band saw motor in response to signals from cabinet door switches such as described herein. It will be appreciated by those of skill in the art that many different arrangements, combinations, configurations, and modifications are possible to achieve the same result. For example, fewer or more switches may be used, one or more door switches may be placed between the source of electrical power and the motor control circuit, the switches may be identical or different, etc. Thus, it will be recognized by those of skill in the art that all such arrangements, combinations, configurations, and modifications are within the scope of this disclosure.

[0174] As noted above, exemplary band saw 10 includes a blade guard assembly 76 which is mounted to elevation assembly 90 and is positioned on the elevation assembly just above upper blade guide assembly 86. The purpose of the blade guard assembly is to substantially enclose the band saw blade between the upper blade guide assembly and the upper cabinet section, thereby reducing the danger to an operator of accidentally contacting the blade.

[0175] Focusing now on Figs. 47-54, exemplary blade guard assembly 76 includes a housing assembly 550 with an elongate base frame 552 having a generally U-shaped crosssection. A housing door 554 is attached to base frame 552 by a hinge 556 that allows the door to pivot from a closed position as shown in Fig. 1, to an open position as shown in Fig. 47. A mounting bracket 558 is attached to the rear of the base frame. The guard assembly is mounted to the elevation assembly by bolt and washer assemblies 560 which pass through holes in mounting bracket 558 and thread into holes in support tube 92.

[0176] In the exemplary embodiment, base frame 552, door 554, and mounting bracket 558 are formed of sheet metal, though some or all of the components may be formed of alternative materials. When mounted to the elevation assembly, the base frame is positioned to surround the sides and rear of blade 70 as it extends downward from upper cabinet section 18. When door 554 is in the closed position, the door encloses the front of the blade above the upper blade guide assembly. When closed, upper cabinet door 24 covers the top of guard door 554 and prevents the guard door from opening. However, when the upper cabinet door is open, the guard door can be pivoted to its open position to allow an operator to remove or install a blade. Oncethe guard door is opened, it prevents the upper cabinet door from fully closing until the guard door is closed.

[0177] As discussed above, the height of the elevation assembly can be adjusted to position the upper blade guide assembly slightly above workpieces of varying heights. Thus, the blade guard assembly raises and lowers with the upper blade guide assembly. When the blade guide assembly is adjusted to its lowest allowable position, the distance between the blade guide assembly and the bottom of the upper cabinet section is at a maximum. The vertical length of housing assembly 550 is sufficient to span this distance so that the blade remains enclosed within the guard housing assembly at all positions of the blade guide assembly.

[0178] When the position of the blade guide assembly is adjusted upward, the top of the blade guard assembly moves upward into the upper cabinet section. A slot or opening 562 in the left side of housing assembly 550 is wide enough to allow upper wheel 52 to fit within the opening so that the top left side of the housing assembly can be positioned inside the outer circumference of the wheel. When the upper blade guide is adjusted to its highest allowable position, the top of housing assembly 550 is above the central hub of the wheel and the right side of the wheel is within the housing assembly.

[0179] Although opening 562 is substantially contained within the upper cabinet section when the upper blade guide is raised near its highest position, the opening becomes exposed below the upper cabinet section as the upper blade guide is lowered. As a result, the base frame will not fully shield an operator from the blade at all elevations of the blade guide assembly. To eliminate this potential hazard, exemplary blade guard assembly 76 includes an automatically expandable and contractible shield mechanism 564 positioned within opening 562. When an operator raises or lowers the blade guide and blade guard assemblies, the height of shield mechanism 564 automatically decreases or increases to cover the portion of the opening below the upper cabinet section.

[0180] The shield mechanism includes two identical shield members 566. Each shield member is a generally rectangular plate with a relatively narrow, vertical slot 568 through the central portion of the plate. A T-shaped catch 570 protrudes outward from the plate above slot 568. The catch is sized to pass through slot 568 when one shield plate is positioned perpendicular to another. Thus, the two shield plates are held together by the latch arm of one shield plate positioned through the slot of the other shield plate. Since the catch can slide along the length of the slot, the two shield plates can slide telescopically relative to one another.

[0181] One shield plate is attached to the lower portion of base frame 552 by a shoulder bolt 572 which threads into a hole in the base frame. This particular shield plate is referred toherein as the “lower shield plate.” The shank of bolt 572 is sized to slide within the slot in the lower shield plate, while the head of bolt is larger than the width of the slot to retain the lower shield plate between the bolt head and base frame. The catch of the lower shield arm is positioned within the slot of the other shield plate, which is referred to herein as the “upper shield plate.” Two retainer posts 574 are attached adjacent opposing corners of the upper shield plate by screws 576. The retainer posts and upper shield sandwich the vertical sides of the base frame around opening 562 so that the shield plates are constrained to slide vertically within the opening.

[0182] Each shield plate includes flexible side fins 578 extending outward from the plate. In the exemplary embodiment, shield plates 566 are formed of injection-molded plastic so that features such as the catch and side fins are integral with the shield plate. However, alternative embodiments may use different materials and / or manufacturing methods to achieve similar functions. In any event, the side fins press against the inner front and rear edges of the base frame to hold the shield plates in vertical alignment within opening 562, while allowing the shield plates to slide vertically relative to the housing assembly.

[0183] A connecting bracket 580 is attached to the upper cabinet section by bolts 582 and nuts 584. A lower limit flange 586 is positioned to engage catch 570 of the upper shield plate to limit the downward travel of the upper shield plate, as shown in Figs. 51 and 53. This ensures the upper shield plate does not drop below the upper cabinet when the blade guide is lowered, thereby exposing a portion of the band saw blade. An upper limit flange 588 is positioned to engage one of the retainer posts to limit the upward travel of the upper shield plate, as shown in Fig. 52. This ensures the upper shield plate does not contact the upper wheel when the blade guide is raised.

[0184] In the exemplary embodiment, side fins 578 are sized to lightly press against the inner front and rear walls of the base frame, as best seen in Fig. 54. The relatively small outward force generated by the flexing fins generates a frictional holding force that tends to hold the shield plates against sliding due to gravity. Nevertheless, the engagement between the flanges of connecting bracket 580 and either the catch of the upper shield orthe retainer post, will overcome this frictional holding force so that the upper shield plate slides relative to the housing assembly. Alternatively, one or both of the shield plates may be configured to freely slide within slot 562 under the force of gravity.

[0185] As best seen in Figs. 51-52, the shield mechanism automatically adjusts or telescopes to cover any portion of opening 562 below the upper cabinet section regardless of the vertical position of the blade guard housing assembly. Since connecting bracket 580 is mounted to the bottom of the upper cabinet section, no portion of opening 562 below the upper cabinet is uncovered at any position of the blade guide and guard housing assemblies. However, the shieldmechanism does not collide or interfere with the upper wheel even when the guard housing assembly is raised to its highest position within the upper cabinet section. In other words, the height of telescoping shield mechanism 564 automatically adjusts as necessary to enclose that portion of the opening on the left side of the blade guard assembly, which is beneath the upper cabinet section, without interfering with the upper wheel. In other words, the left side of the blade guard assembly below the upper cabinet section is always enclosed, despite the opening in the left side of the base frame.

[0186] An alternative way to understand the shield mechanism is that it forms a part of the left side of the blade guard housing. As a result, the height of the left side of the blade guide housing automatically adjusts to achieve the dual goals of enclosing the blade between the upper cabinet section and the upper blade guides without interfering with the upper wheel. This is true for all elevations of the upper blade guides and the blade guard assembly. In other words, the top of the left side of the blade guard housing remains at a constant height (i.e., inside the upper cabinet section but below the upper wheel) even as the remainder of the blade guard housing moves up and down.

[0187] As shown in Figs. 1 and 48, exemplary band saw 10 also includes a task light assembly 600 which is mounted to blade guard assembly 76 by a pair of screws 602. The task light assembly provides lighting below the blade guard assembly to illuminate the blade and the workpiece where it contacts the blade. For other band saws where the task light is mounted to the cabinet or a different structure, it may be necessary to reposition the task light assembly when the positions of either the fence or blade guard change if the repositioned fence and / or blade guard blocks the illumination from the task light. In contrast, an operator using exemplary band saw 10 is not required to separately adjust the position of the task light when the position of either the fence or blade guard is changed. Since task light assembly 600 is mounted to blade guard assembly 76, the position of the task light assembly automatically adjusts when the position of the blade guard changes so that the blade guard assembly cannot block illumination from the task light assembly. Moreover, since the illumination from task light assembly 600 comes from directly above the area where the workpiece will contact the blade, the illumination from the task light assembly cannot be blocked by the fence.

[0188] Turning attention now to Figs. 48 and 55-56, exemplary task light assembly 600 includes a housing base 604. Screws 602 pass through holes formed in the bottom of guard door 554 and thread into holes in the top of housing base 604 to mount the base to the door. A housing cover 606 is attached to the housing base by ultrasonic welding, though other attachment methods such as screws and / or adhesive may be used. Base 604 and cover 606 form a partiallyenclosed housing which contains an LED light strip 608. The light strip is connected to an open / closed toggle microswitch 610 by a standard electrical cable (not shown). Electrical power to drive the light strip is provided by a standard power supply and electrical cable (not shown) which connect to the light strip through the microswitch. In the exemplary embodiment, the electrical cable connects the microswitch to switch box 80, which supplies electrical power to the light switch. When the microswitch is closed, electrical power is connected to the light strip to generate illumination. When the microswitch is open, electrical power is disconnected from the light strip so that no illumination is generated. Cover 606 includes an opening 612 which forms an aperture through which illumination from the light strip passes to illuminate the area where a workpiece contacts the blade.

[0189] A control lever 614 is pivotally connected to base 604 by a rod 616. The lever includes a handle portion 618 which extends outside the housing, and an actuator portion 620 that extends over the microswitch within the housing. When an operator pivots the control lever by pressing the handle portion downward and inward, the actuator portion presses against and toggles the microswitch. Thus, an operator turns the task light illumination on and off by sequentially pressing the handle portion to toggle the microswitch. While one exemplary mechanism has been described to enable an operator to control the task light illumination, those of skill in the art will recognize that many different alternative mechanisms, components, and / or arrangements are possible to achieve the same result using. Therefore, all such alternatives are within the scope of this disclosure.

[0190] As discussed above, table 26 is mounted to cabinet assembly 12 by trunnion assembly 30. The trunnion assembly allows the table to be tilted relative to the cabinet along an axis referred to herein as the “tilt axis.” The tilt axis lies generally along the top surface of the table and extends in a front-to-back direction through the center of the blade where the blade passes through the table insert. When the table is in a generally horizontal position and is perpendicular to the side of the blade, the tilt angle is considered to be zero degrees. As viewed from the front of the band saw, the table can tilt from zero degrees through approximately 45 degrees in a clockwise direction. To adjust the tilt angle of the table, an operator begins by loosening tilt clamp handle 42 (shown in Fig. 3), then tilts the table to the desired angle, and finally retightens the tilt clamp handle to lock the table at the new tilt angle.

[0191] Since the most commonly used tilt angle is zero degrees exemplary band saw 10 includes an adjustable tilt stop mechanism to enable an operator to position the table at zero degrees quickly and easily. The exemplary tilt stop mechanism, indicated generally at 630 in Figs. 57-58, includes a support bracket 632 which is mounted to lower cabinet section 16 by a fastenerassembly 634 including a bolt and multiple washers and nuts. Another fastener assembly 636 is mounted to the support bracket and is adjustable to correctly orient the tilt stop mechanism relative to the table. A positioning bolt 638 is threaded through a hole in the support bracket so that the head of the positioning bolt contacts the lower left edge of table 26 when the table is tilted fully counterclockwise. By adjusting the height of the positioning bolt, the tilt angle of the table can be adjusted to zero degrees when the table is resting on the head of the positioning bolt. A lock nut 640 engages the positioning bolt and prevents unintended adjustment of the positioning bolt.

[0192] Once the tilt angle of the table has been adjusted, it is important for an operator to lock the table against further movement by tightening clamp handle 42. Otherwise, the table may tilt unexpectedly during a cutting operation which could cause serious injury to the operator. When an operator adjusts the tilt angle to any position other than zero degrees, the table will tilt away from the position due to gravity if the operator does not tighten the clamp handle before releasing the table. As a result, the operator will be prompted by the tilting table to tighten the clamp handle so as to maintain the table at the desired tilt angle. However, if the operator tilts the table to the zero degree position so that the table rests on the head of the positioning bolt, the center of gravity of the table assembly, the fence assembly and any workpiece resting on the table may cause the table to remain motionless against the support of the positioning bolt. In other words, an operator might forget to tighten the clamp handle if the table remains in place once released by the operator. It will be appreciated that this can create a hazardous condition because the table may unexpectedly tilt away from zero degrees as the operator begins moving the fence or workpiece across the table, thereby changing the center of gravity.

[0193] To eliminate this potential hazard, exemplary tilt stop mechanism 630 includes a table latch mechanism indicated generally at 642. The table latch mechanism is configured to automatically engage when the table is tilted to approximately zero degrees and to prevent the table from tilting away from zero degrees. Due to manufacturing tolerances, the latch may allow the table to tilt slightly from zero degrees, but the range of movement is limited to just a few degrees. Thus, the table will not unexpectedly tilt substantially even if the operator forgets to tighten the clamp handle. When the operator wants to adjust the tilt angle away from zero degrees, the operator must first manually disengage the table latch mechanism before the table can be tilted.

[0194] Exemplary table latch mechanism 642 includes a movable latch plate 644 which is pivotally mounted to the left side of table 26 by a pair of shoulder bolts 646. The lower portion of latch plate 644 extends below the bottom edge of the table and includes a slot 648 which is sized and shaped to receive a portion of the head of positioning bolt 638. When the table is resting onthe head of the positioning bolt, the left side of the bolt head passes into slot 648. When the bolt head is within the slot on the latch plate, the bolt head prevents the latch plate from rising. As a result, the table cannot tilt because the head of the positioning bolt prevents the left side of the table from lifting. In this position, the latch mechanism is engaged or in a latched condition.

[0195] Latch mechanism 642 also includes a leaf spring 650 which is mounted on shoulder bolts 646. The leaf spring is shaped to bias the lower portion of the latch plate against the side of the table. However, the force of spring 650 can be overcome with clockwise torque on the latch plate as viewed from the front of the band saw. Thus, when the left side of the table is tilted down toward the positioning bolt, the domed head of the bolt will contact the bottom of the latch plate and push it away from the side of the table against the force of the spring. As the table continues tilting, the head of the positioning bolt will move into slot 648, allowing the latch plate to pivot back until the lower portion of the latch plate rests against the side of the table. In this position, the lower portion of the latch plate will be captured beneath the head of the positioning bolt to prevent the table from tilting away from the zero degree position. In other words, the leaf spring enables the latch mechanism to automatically engage or transition to a latched condition when the table is tilted into contact with the positioning bolt.

[0196] The upper portion of the latch plate is bent outward from the side of the table so that the upper and lower portions form a shallow V-shape. While the leaf spring biases the lower portion against the side of the table, the force of the leaf spring can be overcome when an operator pushes the upper portion of the latch plate toward the side of the table. This causes the latch plate to pivot about the bend line between the upper and lower portions. As a result, the lower portion of the latch plate moves away from the side of the table so that the head of the positioning bolt is no longer within slot 648. In this position, the latch mechanism is disengaged or in an unlatched condition so that the operator can tilt the table off the positioning bolt. Thus, to change the tilt angle from zero degrees, an operator must first loosen clamp handle 42 (if tightened), disengage the table latch mechanism by pressing the upper portion of the latch plate toward the side of the table, and then lift the left side of the table upward away from the positioning bolt.

[0197] While one exemplary embodiment of a table latch mechanism has been described above, those of skill in the art will recognize that many modifications and alternative mechanisms are possible to achieve the same function. As just one example, the latch mechanism may be mounted to the cabinet and configured to engage some component or feature associated with the table. Thus, it will be understood that all such modifications and alternatives are within the scope of this disclosure.

[0198] T urning attention now to Fig. 59, further details of table insert assembly 46 can be seen. The table insert functions as a removable section of table 26 and provides a workpiece support surface that is generally parallel and flush with the top surface of the table. During cutting operations, the table insert is installed in the table and covers opening 350 in the table (see Figs. 31-32). The table insert is removable from the table to allow the blade to be removed and installed on the band saw wheels.

[0199] Table insert assembly 46 includes an elongate support plate 660 which is shaped to fit within and substantially fill opening 350. A slot 352 is formed in the support plate to allow the blade to pass through the support plate. Several leveling set screws 662 are threaded into holes 664 in the support plate. When the table insert is installed on the table, the bottoms of the set screws rest on a recessed shelf formed in the table around opening 350. The depth of the set screws in the support plate can be separately adjusted to ensure the top of the support plate is parallel with the table top. A retainer clip 666 is mounted to the underside of the support plate and includes flexible arms which extend downward from the support plate to releasably grip structures formed in the table around the sides of opening 350. The retainer clip holds the table support plate in place unless sufficient upward force on the support plate is applied to overcome the grip of the arms against the table.

[0200] To allow ease of installation of the table insert in the table despite manufacturing tolerances and varying rates of thermal expansion between the table and the support plate, the support plate is slightly undersized relative to opening 350. To prevent excessive play of the support plate within the opening, the support plate is formed of a plastic material with flexible tabs 668 at either side of the support plate. The tabs are formed to protrude outward slightly from the sides of the support plate but are connected to the main body of the support plate by living hinges. As a result, the tabs can flex inward when a moderate amount of sideways force is applied. When the table insert is installed in the table, the tabs contact the sides of the table around opening 350 and flex inward as needed to fit snugly within the opening. Thus, the tabs function to remove any play or looseness of the table insert in the table opening.

[0201] In alternative embodiments, different and / or additional tabs may be formed in the support plate if necessary to remove play in the table insert. Alternatively, separate structures may be mounted or attached to the support plate to remove the play. As a further alternative, components or structures may be mounted to the table or positioned within the table opening to adjustably remove play between the table insert and table opening. Thus, it will be understood that all such alternatives are within the scope of this disclosure.

[0202] As is well-known to those of skill in the art, larger power tools such as exemplary band saw 10 are often partially disassembled when shipped to a customer’s location. This may reduce the potential for damage during shipping and / or may reduce the shipping dimensions. In any case, the customer or an assistant must then complete the assembly of the band saw before it can be safely operated as intended. The extent to which a band saw such as exemplary band saw 10 is disassembled prior to shipment typically varies among manufacturers, brands, and / or models. Some components which are commonly shipped unassembled are the table, the table extension wing, the rip fence rail, the rip fence, the blade, etc. While some unassembled components are relatively easy for a customer to install, other components may be more difficult due to a variety of factors including the component’s size and weight, the assembly mechanism, etc.

[0203] As can be seen in Figs. 1 and 2, the table assembly of exemplary band saw 10, which includes the table, extension wing, and rip fence rail, extends outward from the cabinet. Thus, the shipping dimensions of the band saw may be larger if the table assembly is assembled prior to shipment. Furthermore, the table assembly has substantial mass which may create excessive strain on the trunnion assembly during shipment if the table assembly is mounted to the trunnion assembly. Therefore, it may be desirable to ship a band saw such as exemplary band saw 10 with the table assembly uninstalled. Indeed, some components of the table assembly such as the rail and the extension wing may be disassembled from the table itself. In which case, the customer will first mount the table to the band saw before installing the other components. Nevertheless, the substantial mass of the table may make it difficult for one person to install if the person must manually support the table while fastening it to the trunnion assembly. While one or more assistants may facilitate the installation, some customers may not have a capable assistant who is readily available.

[0204] To enable one person to mount table 26 to the trunnion assembly both safely and easily, exemplary band saw 10 is shipped with a temporary positioning block 700 as shown in Figs. 60 and 61. The positioning block may be used by the customer to support the table on lower cabinet section 16 and align the table to trunnion brackets 34. As a result, the customer or assembler is not required to support the table while fastening the table to the trunnion brackets.

[0205] Exemplary positioning block 700 is molded from expanded polystyrene though other materials may alternatively be used including othertypes of foam, cardboard, plastic, wood, etc. The upper surface of the positioning block is contoured to include various features to facilitate assembly of the table. Such features include markings 702 which instruct the assembler on how the positioning block should be positioned on the cabinet. Other features include raised areas 704separated by channels 706. The raised areas and channels mate with the contours of the lower surface of the table so that the table rests securely on the positioning block.

[0206] Similarly, the lower surface of the positioning block is contoured with various features to engage the cabinet and retain the positioning block in a stable and stationary position once the positioning block is correctly positioned on the lower cabinet section. Such lower surface features include downwardly projecting overhanging elements (also referred to herein as “overhangs”) 708 which are separated by a base surface 710. The base surface is sized to extend across the top of the lower cabinet section while the overhangs extend downward at the front and back of the lower cabinet section to prevent the positioning block from sliding or otherwise moving off the top of the lower cabinet section. As will be discussed in more detail below, another feature of the lower surface is a channel 712 which is positioned to engage the lower cabinet door.

[0207] Fig. 62 shows the exemplary positioning block in place on lower cabinet section 16 prior to placement of the table on the positioning block. The base surface of the positioning block rests on top surface 714 of the lower cabinet section, with the overhangs extending downward at the front and back of the lower cabinet section. Lower cabinet door 22 is opened by approximately 11 degrees from its closed position to fit within channel 712, which is formed at a similar angle relative to the front of the cabinet. The partial opening of the lower cabinet door increases the effective front-to-back width of the lower cabinet section to provide increased support and stability for the positioning block. Alternative embodiments may utilize a different open angle for the door, or the door may remain closed during table installation.

[0208] Each exemplary trunnion bracket 34 includes two fastener engagement locations 716. In the exemplary embodiment, the fastener engagement locations on the trunnion brackets include untapped holes with a substantially flat surface surrounding the holes. The holes and surrounding surfaces are arranged to engage matching fastener engagement locations (not shown) on the underside of table 26. The fastener engagement locations on the table include tapped holes surrounded by substantially flat surfaces. Thus, the table can be fastened to the trunnion brackets by bolts which pass through the holes in the trunnion brackets and thread into the holes in the table. Alternatively, other types of fasteners may be used to fasten the table to the trunnion brackets. In any event, once the table is fastened to the trunnion brackets, it is also pivotally fastened to the trunnion block and thereby the lower section of the cabinet. Thus, the trunnion brackets can also be thought of as a table mount which is pivotally supported by the cabinet, and which pivotally mounts the table to the cabinet.

[0209] Once the positioning block is properly placed on the top of the upper cabinet section, an installer can place the table on top of the positioning block as shown in Figs. 63 and64. In the exemplary embodiment, the positioning block is shaped to support the table in a generally horizontal orientation. Consequently, the trunnion brackets should be adjusted to an approximately zero tilt position prior to placing the table on the positioning block. In alternative embodiments, the positioning block may be shaped to support the table in a non-horizontal orientation. In any case, the table is stably supported by both the positioning block and trunnion brackets so that the installer is not required to manually support the weight of the table once it is placed on the positioning block.

[0210] The thickness of the positioning block, including raised areas 704 and channels 706, are sized to locate the bottom surface of the table at generally the same height as the top surfaces of the trunnion brackets. In particular, the size and shape of the positioning block ensures the fastener locations on the underside of the table are generally at the same height as the fastener locations on the trunnion brackets. In other words, the positioning block aligns the fastener locations on the table with the fastener locations on the trunnion brackets in at least the vertical direction. Depending on the exact position of the positioning block relative to the trunnion brackets, some or all of the table fastener locations may also be aligned with the corresponding trunnion bracket fastener locations in a front-to-back direction and / or a side-to-side direction. Conversely, none of the fastener locations may be aligned when the table is first placed on the positioning block. Nevertheless, the installer need only slide the table horizontally (i.e., without lifting the table) until all the fastener locations are aligned. At which point, the fasteners may be installed to fasten the table to the trunnion brackets. In the exemplary embodiment, each fastener location is engaged by a fastener assembly including a bolt, a flat washer, and a lock washer.

[0211] Once the bolts have been tightened and the table is securely fastened to the trunnion brackets, the temporary positioning block is no longer needed. Indeed, the exemplary positioning block will interfere with normal operation of exemplary band saw 10 by preventing the lower cabinet door from closing, and by preventing the table from tilting in a counterclockwise direction (as viewed from the front of the band saw). Thus, the positioning block should be removed before operating the band saw. This is accomplished by tilting the table in a clockwise direction until the table is no longer resting on the positioning block and there is sufficient clearance to remove the positioning block. Once removed, the positioning block may be disposed of or retained for possible reuse in the future. In alternative embodiments, the positioning block may be configured to retract or move to a different position that does not interfere with operation of the band saw, and thereby remain on the band saw during operation. As a further alternative, the positioning block may be configured to remain in place without interfering with operation of the band saw.INDUSTRIAL APPLICABI LITYThe components, mechanisms, assemblies, structures, and methods described herein are applicable to power tools, and more particularly to band saws of all sizes, types, and intended uses.It is believed that the disclosure set forth above encompasses multiple distinct inventions with independent utility. While each of these inventions has been disclosed in its preferred form, the specific embodiments thereof as disclosed and illustrated herein are not to be considered in a limiting sense as numerous variations are possible. The subject matter of the inventions includes all novel and non-obvious combinations and sub-combinations of the various elements, features, functions and / or properties disclosed herein. No single feature, function, element, or property of the disclosed embodiments is essential to all of the disclosed inventions. Similarly, where the claims recite “a” or “a first” element or the equivalent thereof, such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements.It is believed that the following claims particularly point out certain combinations and subcombinations that are directed to one of the disclosed inventions and are novel and non-obvious. Inventions embodied in other combinations and sub-combinations of features, functions, elements and / or properties may be claimed through amendment of the present claims or presentation of new claims in this or a related application. Such amended or new claims, whether they are directed to a different invention or directed to the same invention, whether different, broader, narrower, or equal in scope to the original claims, are also regarded as included within the subject matter of the inventions of the present disclosure.

Claims

CLAIMS1. A band saw, comprising: a support structure, two or more wheels rotatably supported by the support structure, a band blade mounted around the wheels; and a blade guide assembly including a blade guide mounting block supported by the support structure, and at least a first blade guide member attached to the mounting block and positioned to limit deflection of the blade in a first direction, where the first blade guide member is eccentrically attached to the mounting block such that the position of the first blade guide member is adjustable in the first direction relative to the mounting block.

2. The band saw of claim 1 , where the blade guide assembly includes a second blade guide member attached to the mounting block and positioned to limit deflection of the blade in a second direction, and where the second blade guide member is eccentrically attached to the mounting block such that the position of the second blade guide member is adjustable in the second direction relative to the mounting block.

3. The band saw of claim 2, where the position of the second blade guide member is adjustable independent of the position of the first blade guide member.

4. The band saw of claim 2, where the eccentric attachment of the second blade guide member to the mounting block is independent of the eccentric attachment of the first blade guide member to the mounting block.

5. The band saw of claim 1 , where the position of the first guide member is adjustable without the use of tools.

6. The band saw of claim 1 , where the first guide member is attachable to, and detachable from, the mounting block without the use of tools.

7. The band saw of claim 1 , where the blade guide assembly further includes a detent mechanism configured to generate a tactile stimulus to an operator when the operator adjusts the position of the first guide member by a defined increment.

8. A band saw, comprising: a cabinet; two or more wheels rotatably supported by the cabinet; a band blade mounted around the wheels; a motor coupled to drive at least one of the wheels; a mounting block supported by the cabinet; an attachment mechanism including an axle component supported by the mounting block so as to be rotatable relative to the mounting block about a rotational axis; and a blade guide member mounted to the attachment mechanism in a position that is asymmetric with the rotational axis, and configured to limit deflection of the blade in at least one direction;9. The band saw of claim 8 where the axle component is rotatable by an operator without the use of tools.

10. The band saw of claim 9, further comprising a detent mechanism configured to generate tactile stimuli perceptible to the operator when the operator rotates the axle component.11 . The band saw of claim 8 where the mounting block includes a cavity and an automatic retention mechanism, where the cavity is shaped to receive the axle component, and where the automatic retention mechanism is configured to engage the axle component, without intervention by a user, when the axle component is fully seated within the cavity, and where the automatic retention mechanism is configured to apply a restraining force on the axle component tending to hold it in the fully seated position.

12. A band saw, comprising: a cabinet; two or more wheels rotatably supported by the cabinet; a band blade mounted around the wheels; a motor coupled to drive at least one of the wheels; a mounting block supported by the cabinet; an attachment mechanism; and a blade guide member mounted on the attachment mechanism; where the attachment mechanism is configured to attach the blade guide member to the mounting block when the attachment mechanism engages the mounting block; and where the attachment mechanism is maneuverable by an operator to alternately engage and disengage the mounting block without the use of tools.

13. A band saw, comprising: a support structure, two or more wheels rotatably supported by the support structure, a band blade mounted around the wheels; a motor configured to drive at least one of the wheels; a table supported by the support structure and having an upper surface configured to support a workpiece; a rail mounted to the workpiece support table; and a fence assembly mountable to the rail, the fence assembly including a carrier assembly configured to slide along to the rail, a workpiece guide assembly configured to extend over a portion of the upper surface of the table, and to align a workpiece relative to the blade, and a clamp mechanism operable to clamp the workpiece guide assembly to the carrier assembly by applying a clamping force to the workpiece guide assembly in a direction generally perpendicular to the top surface of the table, where the clamp mechanism includes a control member movable by an operator in a direction generally parallel to the upper surface of the table to apply the clamping force.

14. The band saw of claim 13, where the control member is positioned beneath the upper surface of the table.

15. The band saw of claim 14, where the rail includes an upper surface and the control member is positioned above the upper surface of the rail.

16. The band saw of claim 13, where the control member is pivotally movable by an operator to apply the clamping force.

17. The band saw of claim 13, where the rip fence assembly includes a positioning plate assembly mounted to the carrier assembly, where the orientation of the positioning plate assembly relative to the carrier assembly is pivotally adjustable in a plane that is generally parallel to the upper surface of the table, and where the clamp mechanism clamps the workpiece guide assembly to the carrier assembly by clamping the workpiece guide assembly to the positioning plate assembly.

18. A band saw, comprising: a support structure, two or more wheels rotatably supported by the support structure, a motor configured to drive at least one of the wheels; a table supported by the support structure and having an upper surface with a front edge, the upper surface being configured to support a workpiece; a band blade mounted around the wheels in a continuous path such that a portion of the blade passes through the upper surface of the table; a rail mounted to the front edge of the workpiece support table; and a fence assembly mountable to the rail, the fence assembly including a carrier assembly configured to slide along the rail, a positioning plate assembly adjustably mounted to the carrier assembly, and a workpiece guide assembly mounted to the positioning plate assembly so as to extend over a portion of the upper surface of the table, where the workpiece guide assembly is configured to align a workpiece relative to the blade, where the positioning plate assembly is pivotally adjustable relative to the carrier assembly about a pivot axis that is generally perpendicular to the upper surface of the table and spaced apart from the front edge of the table in a direction toward the portion of the blade that passes through the upper surface of the table.

19. The band saw of claim 18, where the pivot axis is proximate the portion of the blade that passes through the upper surface of the table.

20. The band saw of claim 18, where the pivot axis is within approximately 1 inch from the portion of the blade that passes through the upper surface of the table.21 . The band saw of claim 18, where at least one of the carrier assembly or the positioning plate assembly includes one or more arcuate features which are coaxial about the pivot axis, and where the adjustment of the positioning plate assembly relative to the carrier assembly is constrained by the one or more arcuate features.

22. The band saw of claim 18, where the one or more arcuate features includes at least one arcuate slot formed in the positioning plate assembly.

23. A band saw, comprising: a cabinet assembly, two or more wheels rotatably supported by the cabinet assembly; a motor configured to drive at least one of the wheels; a workpiece support table supported by the cabinet assembly; a band blade mounted around the wheels; a rail mounted to the workpiece support table; and a fence assembly mountable to the rail, the fence assembly including a carrier assembly configured to slide along the rail, a workpiece guide surface supported by the carrier assembly and configured to position a workpiece relative to the blade for a desired width of cut, and a drift angle adjustment mechanism configured to adjust the drift angle between the workpiece guide surface and the blade, where the drift angle adjustment mechanism is operable by a user of the band saw to adjust the drift angle by at least 1 degree without changing the width of cut by more than 0.02 inch.

24. The band saw of claim 21 where the drift angle adjustment mechanism is operable to adjust the drift angle without the use of tools.

25. The band saw of claim 21 where the drift angle adjustment mechanism includes a clamp movable between an unclamped position in which the drift angle can be adjusted and a clamped position in which the drift angle cannot be adjusted, and a biasing mechanism configured to bias the workpiece guide surface against movement relative to the carrier assembly as the clamp is moved from the unclamped position to the clamped position.

26. A band saw, comprising: a cabinet assembly, two or more wheels rotatably supported by the cabinet assembly; a motor configured to drive at least one of the wheels; a table supported by the cabinet assembly and having an upper surface configured to support workpieces; a band blade mounted around the wheels; an elongate rail configured to support a rip fence; and a rail pivot coupling configured to pivotally attach the rail to the table.

27. The band saw of claim 26, where the rail is pivotal between a first position in which the elongate axis is generally parallel to the upper surface of the table such that neither end of the rail extends above the upper surface of the table, and a second position where one end of the rail extends above the upper surface of the table.

28. The band saw of claim 27, where the rail pivots more than 90 degrees when pivoting from the first position to the second position.

29. The band saw of claim 28, where the pivot coupling limits the maximum pivot angle of the rail to less than 120 degrees.

30. The band saw of claim 27, further comprising a rail support bracket attached to the table and configured to support one end of the rail when it is in the first position.31 . The band saw of claim 27, further comprising a magnetic positioned to exert a magnetic retention tending to hold the rail against the support bracket when the rail is in the first position.

32. The band saw of claim 26, where the rail is operable to support a rip fence when in the first position, and where the rail is not operable to support a rip fence when in the second position.

33. The band saw of claim 27, where the upper surface of the table includes an opening that extends from a central area to a front edge of the upper surface, and where the rail extends across the opening when in the first position but not when in the second position.

34. The band saw of claim 33, further comprising a crossbar movable between an alignment position and a retracted position, where the crossbar is configured to engage the table on both sides of the opening so as to align the upper surface of the table on either side of the opening in a common plane when the crossbar is in the alignment position, where the crossbar is configured to disengage from the table on at least one side of the opening when in the retracted position, and where the crossbar automatically moves to the retracted position when the rail is pivoted from the first position to the second position.

35. The band saw of claim 34, where the crossbar automatically moves to the alignment position when the rail is pivoted from the second position to the first position.

36. A band saw, comprising: a cabinet assembly, two or more wheels rotatably supported by the cabinet assembly; a motor configured to drive at least one of the wheels; a workpiece support table supported by the cabinet assembly and having an upper surface and a first edge, where the upper surface includes an opening extending from the first edge to a generally central region of the upper surface; a band blade mounted on the wheels to move in a continuous path that passes through the opening in the table; and an alignment crossbar movably mounted to the table, where the crossbar is movable relative to the table between a first position and a second position, where the crossbar extends fully across the opening when in the first position to engage portions of the table on both sides of the opening, where the crossbar does not engage portions of the table on both sides of the opening when the crossbar is in the second position, and where engagement of the crossbar with portions of the table on both sides of the opening causes the upper surface of the table on both sides of the opening to align substantially within a common plane.

37. The band saw of claim 36, where the alignment crossbar is mounted to the table adjacent the first edge.

38. The band saw of claim 36, where the workpiece support table includes a bottom surface having an alignment channel formed on each side of the opening, and where the crossbar is disposed within the alignment channels on each side of the opening when in the first position.

39. The band saw of claim 36, where the crossbar is movable by an operator without the use of tools.

40. A band saw, comprising: a cabinet, two or more wheels rotatably supported by the cabinet; an electrically-driven motor configured to drive at least one of the wheels; a control circuit configured to connect electrical power to drive the motor; a workpiece support table supported by the cabinet; a band blade mounted around the wheels; a cabinet door having a first edge and a second edge, where the first edge of the door is pivotally attached to the cabinet; and a door latch assembly configured to move between a latched and unlatched condition, where the door latch assembly latches the second edge of the door to the cabinet when in the latched condition; where the door latch assembly includes an electrical switch that switches between a first state and a second state, where the electrical switch is in the first state when the door latch assembly is in the latched condition, where the electrical switch is in the second state when the door latch assembly is in the unlatched condition, and where the electrical switch is electrically connected to the control circuit; and where the control circuit is configured to not to connect electrical power to the motor when the electrical switch is in the second state.41 . The band saw of claim 40, where the door latch assembly includes a catch member and a shelf, where the door latch assembly is in the latched condition when the catch is engaged on the shelf, and where the catch switches the electrical switch to the first state when the catch engages the shelf.

42. A band saw, comprising: a cabinet including an upper section and a lower section, two or more wheels rotatably supported by the cabinet; a motor configured to drive at least one of the wheels; a workpiece support table supported by the lower section of the cabinet; a band blade mounted around the wheels; a blade guard housing movably mounted to the cabinet, where the vertical position of the blade guard housing relative to the upper section of the cabinet is adjustable between a first position and a second position, where the second position is lower than the first position, where the blade guard housing has an opening, and where a larger portion of the opening is positioned below the upper section when the blade guard housing is in the second position than the first position; and a contractible shield mechanism connected to the upper section of the cabinet, where the shield mechanism is positioned to cover the portion of the opening in the housing which is below the upper section of the cabinet, where the shield mechanism has a length below the upper section of the cabinet, and where the length of the shield mechanism below the upper section of the cabinet increases as the position of blade guard housing is lowered from the first position to the second position.

43. The band saw of claim 42, where the shield mechanism includes one or more rigid members positioned to cover the portion of the opening in the housing that is below the upper section of the cabinet.

44. The band saw of claim 43, where the shield mechanism includes a first rigid member and a second rigid member, and where the second rigid member is coupled to slide along the first rigid member when the vertical position of the blade guard housing is adjusted.

45. The band saw of claim 44, where the second rigid member is identical to the first rigid member.

46. The band saw of claim 43, where the one or more rigid members include plural flexible features configured to slidably engage the blade guard housing and to maintain the orientation of the rigid members relative to the blade guard housing.

47. A band saw, comprising: a cabinet, two or more wheels rotatably supported by the cabinet; a motor configured to drive at least one of the wheels; a workpiece support table supported by the cabinet; a band blade mounted around the wheels; a blade guard assembly mounted to the cabinet and positioned to at least partially enclose a portion of the blade, where the height of the blade guard assembly is adjustable relative to the cabinet; and a task light mounted to the blade guard assembly and positioned to illuminate an area below the blade guard assembly, where the height of the task light relative to the cabinet adjusts with the height of the blade guard assembly.

48. The band saw of claim 47, where the blade guard assembly has a bottom portion, and where the task light is mounted to the bottom portion of the blade guard assembly.

49. The band saw of claim 47, where the blade guard assembly includes a housing and a door pivotally attached to the housing, and where the task light is mounted to the door of the blade guard assembly.

50. A band saw, comprising: a cabinet, two or more wheels rotatably supported by the cabinet; a motor configured to drive at least one of the wheels; a band blade mounted around the wheels; a workpiece support table pivotally mounted to the cabinet, where the table is pivotal between a first angle relative to the cabinet and a second angle relative to the cabinet; and a table latch mechanism configured to automatically latch the table at the first angle when the table is pivoted from the second angle to the first angle, where the table is prevented from pivoting away from the first angle when the table is latched by the latch mechanism.51 . The band saw of claim 50, where the latch mechanism is releasable by an operator without the use of tools, and where the table is pivotal away from the first angle when an operator releases the latch mechanism.

52. The band saw of claim 50, where the latch mechanism includes an adjustment mechanism operable to adjust the first angle.

53. The band saw of claim 50, where the latch mechanism includes a table support member configured to support the table at the first angle.

54. The band saw of claim 53, where the support member is adjustable to adjust the first angle.

55. A band saw assembly, comprising: a temporary positioning block; and a band saw operable to cut workpieces when fully assembled, including a support structure, two or more wheels rotatably supported by the support structure, a band saw blade mountable around the wheels, a motor configured to drive at least one of the wheels, a table mount supported by the support structure and including a first set of one or more fastener engagement locations, a workpiece support table including a second set of one or more fastener engagement locations, and one or more fasteners positionable by an operator to engage both the first and second set of fastener engagement locations when the sets are aligned, and to fasten the table to the table mount when the one or more fasteners are engaged with the first and second sets of fastener engagement locations; where the temporary positioning block is usable to support the table at a position relative to the support structure such that the second set of fastener engagement locations are aligned in at least one direction with the first set of fastener engagement locations; and where the temporary positioning block is disposable and unnecessary to the operation of the band saw after the table is fastened to the table mount.

56. The band saw of claim 55, where the second set of fastener engagement locations are aligned in at least one direction with the first set of fastener alignment locations when the positioning block is placed on top of a portion of the support structure and the table is placed on top of the positioning block.

57. The band saw of claim 56, where the support structure includes a lower cabinet section, and where the second set of fastener engagement locations are aligned in at least one direction with the first set of fastener alignment locations when the positioning block is placed on top of the lower cabinet section and the table is placed on top of the positioning block.

58. The band saw of claim 56, where at least a portion of the table mount is pivotally supported by the cabinet such that the table is pivotal through an angular range relative to the cabinet when fastened to the table mount, and where the table is prevented from pivoting through the entire angular range while the positioning block remains on top of the portion of the support structure.

59. The band saw of claim 55, where the table has a substantially flat upper surface and a substantially contoured lower surface, and where the positioning block has a substantially contoured upper surface that mates with the lower surface of the table when the table is placed on top of the positioning block.

60. A band saw, comprising: a cabinet assembly, two or more wheels rotatably supported by the cabinet assembly, a band blade mounted around the wheels; a motor coupled to drive at least one of the wheels; a table mount supported by the cabinet assembly and including a first set of one or more fastener engagement locations; a workpiece support table including a second set of one or more fastener engagement locations; a temporary positioning block configured to position the table relative to the cabinet assembly such that the second set of fastener engagement locations are aligned in at least one direction with the first set of fastener engagement locations; and one or more fasteners positionable by an operator to engage both the first and second set of fastener engagement locations when the sets are aligned, and to fasten the table to the table mount when the one or more fasteners are engaged with the first and second sets of fastener engagement locations; where the temporary positioning block is disposable and unnecessary to the operation of the band saw after the table is fastened to the mounting block.

61. A method of assembling a workpiece support table to a band saw, where the band saw includes a cabinet assembly, a table mount supported by the cabinet assembly, and one or more fasteners, the method comprising: orienting the cabinet assembly in an upright and operable position; placing a temporary positioning block on a portion of the cabinet assembly; placing the workpiece support table on the temporary positioning block such that the workpiece support table is at least partially supported by the positioning block; fastening the workpiece support table to the table mount with the one or more fasteners; and removing the temporary positioning block from the cabinet assembly and the workpiece support table before operating the band saw.

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