Table saw fence with a tension adjustment cam

Abstract

Table saw fence with a tension adjustment cam. The fence assembly of a saw apparatus includes a fence, a sliding mechanism coupled to one end of the fence, and a tension mechanism coupled to the other end of the fence. The fence assembly includes a handle supported on the sliding mechanism via a cam. The handle is rotatable relative to the cam between a first position and a second position, in which the fence assembly is fixed relative to a track in the first position and movable relative to the track in the second position. The fence assembly includes a tension member connected at one end to the handle and at the other end to the tension mechanism. The cam is rotatable relative to the sliding mechanism about a cam rotation axis, and rotation of the cam relative to the cam rotation axis provides adjustment of the tension applied by the tension member.

Description

BACKGROUND OF THE INVENTION

[0001] Table saws of various designs include a frame and an upward-facing work surface having an opening through which a blade extends. The table saw may include a movable fence that is supported on tracks on opposite sides of the work surface. The fence provides a guiding surface against which the material to be cut is located. During a cutting operation, as the material is cut by the saw blade, the material rests on the work surface while sliding along the fence. Since the fence is set perpendicular to the work surface and generally parallel to the blade alignment, the fence enables the table saw to provide accurate, straight, and reproducible cuts. The fence can be positioned relative to the work surface by sliding the fence along the track to a desired spacing from the blade and by using a locking mechanism to secure the fence in the desired position.

[0002] Some fence assemblies include a locking mechanism having front and rear engagement members that engage tracks on both the front and rear sides of the saw table. Such mechanisms typically include a linkage that transfers mechanical force from the front-side track to the rear-side track. The linkage can be in the form of a push rod that advances toward the rear side of the saw table and experiences a compressive force in use. Alternatively, the linkage can be a tension member such as a rod or a flexible cable that transfers a tensile force from the front side of the saw table to the rear side. In many cases, the force applied via the linkage creates a vertical frictional reaction force on the rear engagement member and a counter force that is also a vertical frictional reaction force on the front engagement member. These vertical frictional reaction forces create a resistance to prevent movement of the engagement members along the tracks, thereby securing the fence in place during normal applications (e.g., in applications where the force orthogonal to the fence surface is less than 100 N).

[0003] A tight engagement is required between the front and rear engagement members and the corresponding front or rear tracks to achieve accurate and reproducible alignment of the fence relative to the saw table for each position of the fence along the track. The tightness of the engagement is determined by the amount of force applied via the linkage (e.g., a tension member), which can be positively or negatively affected by manufacturing tolerances of the fence assembly, cable stretching, wear of the assembly components during use, etc. In addition, the tension member and the associated mechanism of the table saw fence are typically positioned inside the fence to be protected from sawdust and other environmental damage risks. This internal positioning of the tension member makes it difficult to access the tension member for tension adjustment. For these reasons, it is desirable to be able to adjust the amount of tension applied by the tension member to ensure accurate and reproducible fence alignment. In addition, it is desirable to be able to easily access the tension adjustment mechanism from outside the fence and the front side of the saw table. SUMMARY OF THE INVENTION

[0004] In some aspects, the fence assembly is configured to guide a workpiece relative to the blade of a sawing device and is supported to translate along a track relative to the working surface of the sawing device. The fence assembly includes a fence having a first fence end and a second fence end opposite the first fence end, and a sliding mechanism coupled to the first fence end and supported on a first track in the track. The fence assembly includes a tensioning mechanism coupled to the second fence end and supported on a second track in the track, and a handle supported on the sliding mechanism via a cam. The handle is rotatable relative to the cam between a first position and a second position, in which the fence assembly is fixed relative to the track in the first position, and the fence assembly is movable relative to the track in the second position. Additionally, the fence assembly includes a tension member. The tension member includes a first end coupled to the handle and a second end opposite the first end and coupled to the tensioning mechanism. The cam is rotatable relative to the sliding mechanism about a cam rotation axis, and rotation of the cam relative to the cam rotation axis provides adjustment of the tension applied by the tension member.

[0005] In some embodiments, the tension member is coupled to the handle via a pivot pin, rotation of the cam relative to the cam rotation axis changes the position of the pivot pin relative to the first fence end, and a change in the position of the pivot pin relative to the first fence end changes the tension applied by the tension member to the tensioning mechanism.

[0006] In some embodiments, the handle is rotatable relative to the cam about a handle rotation axis, and the cam rotation axis is parallel to and spaced apart from the handle rotation axis.

[0007] In some embodiments, the tension member has a first end connected to the handle via a pivot pin that defines a tension member connection axis. The handle is rotatable relative to the cam about a handle rotation axis, and the handle rotation axis is parallel to and spaced apart from the tension member connection axis.

[0008] In some embodiments, the handle is rotatable between a first position and a second position, in which the tension member is under a first tension and the sliding mechanism and the tensioning mechanism are fixed relative to the track in the first position, and the tension member is under a second tension and the front and rear housings are movable relative to the track in the second position. The second tension is less than the first tension.

[0009] In some embodiments, the tension member is a rod.

[0010] In some embodiments, the cam includes an outer bearing surface rotatably supported on a housing of the sliding mechanism. Additionally, the cam includes an inner bearing surface rotatably supporting the handle, in which the inner bearing surface is eccentrically positioned relative to the outer bearing surface.

[0011] In some embodiments, the backrest assembly includes a backrest tension adjustment mechanism configured to adjust the tension of the tension member. The backrest tension adjustment mechanism includes a cam. The cam includes an outer bearing surface rotatably supported on the housing of the sliding mechanism and an inner bearing surface rotatably supporting the handle. The inner bearing surface is eccentrically positioned relative to the outer bearing surface. The backrest tension adjustment mechanism includes an adjustment screw coupled to the cam and engaging the housing. The adjustment screw is configured to adjust the rotational orientation of the cam relative to the housing.

[0012] In some embodiments, the cam is rotatable relative to the housing between a first cam rotational orientation and a second cam rotational orientation, in which the tension member has a first tension in the first cam rotational orientation and a second tension in the second cam rotational orientation, and the first tension is greater than the second tension.

[0013] In some embodiments, the adjustment screw is configured to fix the cam to the housing in a desired cam rotational orientation.

[0014] In some embodiments, the adjustment screw enables the cam to be rotatable relative to the front housing between a first cam rotational orientation and a second cam rotational orientation, in which the tension member connection axis is at a first distance from one end of the backrest in the first cam rotational orientation and at a second distance from the said end of the backrest in the second cam rotational orientation. The first distance is different from the second distance, and the amount of tension provided in the tension member corresponds to the distance of the tension member connection axis from the said end of the backrest.

[0015] In some embodiments, when the handle is in a first position, the handle obstructs access to the adjustment screw, and when the handle is in a second position, the handle does not obstruct access to the adjustment screw.

[0016] In some embodiments, the cam includes a first annular member and a second annular member. The second annular member is separable from the first annular member and is keyed into the first annular member to rotate in unison with the first annular member.

[0017] In some embodiments, the cam includes a first annular member and a second annular member. The first annular member includes a first inner edge and a first outer edge surrounding the first inner edge. The first annular member includes a first handle-facing surface extending between the first outer edge and the first inner edge and a first protrusion protruding from the first handle-facing surface. The second annular member includes a second inner edge and a second outer edge surrounding the second inner edge. The second annular member includes a second handle-facing surface extending between the second outer edge and the second inner edge and a second protrusion protruding from the second handle-facing surface. The second protrusion includes a groove for receiving and engaging the first protrusion.

[0018] In some embodiments, an adjustment screw is coupled to the cam and engages a sliding mechanism. The adjustment screw is configured to adjust a rotational orientation of the cam relative to the sliding mechanism.

[0019] In some embodiments, the handle includes a cylindrical shaft projecting bilaterally from a first end of the handle. A first annular member is disposed on one side of the handle and a first portion of the shaft is supported on a first inner edge, and a second annular member is disposed on the other side of the handle and a second portion of the shaft is supported on a second inner edge.

[0020] In some aspects, a saw device includes a fence assembly supported relative to a working surface of the saw device via a first track and a second track of the saw device. The fence assembly includes a fence and a sliding mechanism disposed at a first end of the fence. The sliding mechanism includes a housing configured to engage the first track. The fence assembly includes a tensioning mechanism disposed at a second end of the fence. The tensioning mechanism is configured to engage the second track. The fence assembly includes a handle supported on the sliding mechanism. The handle is movable relative to the sliding mechanism between a first position and a second position. The fence assembly includes a tensioning member having a first end coupled to the handle and a second end coupled to the tensioning mechanism. Additionally, the fence assembly includes a fence tension adjustment mechanism configured to adjust a tension of the tensioning member. When the handle is in the first position, a first tension is applied by the tensioning member to the tensioning mechanism. When the handle is in the second position, a second tension is applied by the tensioning member to the tensioning mechanism. The second tension is less than the first tension. The fence tension adjustment mechanism includes a cam supported on the sliding mechanism for rotation about a cam axis of rotation. The cam is configured to support the handle for rotation about a handle axis of rotation parallel to and spaced from the cam axis of rotation. The fence tension adjustment mechanism includes an adjustment screw passing through an opening in the cam and engaging the housing. The adjustment screw is configured to adjust a rotational position of the cam relative to the housing.

[0021] In some embodiments, the table saw fence assembly includes a linkage that transfers mechanical force from a front track to a rear track using a tension member such as a rigid rod or a flexible cable to transfer tension between front and rear engagement members. In the illustrated embodiment, the tension member transfers a pulling force from a track at the front side of the saw table to a track at the rear side of the saw table. At the rear track, the rear engagement member is a tension mechanism including a rod that is connected to the top of the fence via a pivot pin, and the tension member engages the rod below the pivot pin and transfers force to the rod to pull the rod toward the rear track. The rod engages the rear track and applies a compressive force to the rear track, resulting in a vertical frictional reaction force that prevents movement of the fence relative to the top surface of the saw table. At the front track, the front engagement member is a sliding mechanism including a handle that is pivotally coupled to the sliding mechanism via a rotatable cam. The tension member is coupled to the handle via a pivot pin that defines a tension member connection axis. The tension member connection axis is eccentric with respect to the axis of rotation of the handle, and rotation of the handle causes the tension member to be pulled toward the front track, whereby the transmission member transfers force to the handle to pull the rod toward the rear track. The amount of tension in the tension member can be adjusted by using a fence tension adjustment mechanism that includes a cam having an internal eccentric pivot. More specifically, a change in the rotational orientation of the cam with respect to the sliding mechanism results in a change in the position of the tension member connection axis relative to one end of the fence, and thus an increase or decrease in the effective length of the tension member. An increase or decrease in the effective length of the tension member results in an increase or decrease in the tension applied to the tension and sliding mechanisms via the tension member. Rotation of the cam is achieved by using an adjustment screw located on the front side of the table saw and thus easily accessible to the user. This can be compared to some conventional table saws in which the user must walk to the rear side of the saw table, reach near the saw, or remove the fence to access the adjustment mechanism. By providing adjustability of the rotational orientation of the cam, the fence tension adjustment mechanism allows for fine adjustment of the fence locking force. Further advantageously, the adjustment mechanism disclosed herein provides anti-adjustment protection while under load and with the fence in place. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a perspective view of a portion of a saw apparatus showing the top surface of the saw table and the fence assembly.

[0023] Figure 2 is a side view of the top surface of the saw table and the fence assembly.

[0024] Figure 3 is a cross-sectional view of the top surface of the saw table and the fence assembly taken along line 3-3 of Figure 1 the

[0025] Figure 4 is an enlarged view of a portion of Figure 4 enclosed by a dashed line and labeled " Figure 3 ".

[0026] Figure 5 is an enlarged view of a part that is circled by a dashed line and labeled " Figure 5 ". Figure 3 In Figure 5 solid lines are used to show the handle and pivot pin in the first position, and dashed lines are used to show the handle and pivot pin in the second position.

[0027] Figure 6 is an exploded perspective view of the backrest assembly.

[0028] Figure 7 is a perspective view of the backrest separated from the backrest assembly.

[0029] Figure 8 is a top perspective view of the tensioning mechanism of the backrest assembly.

[0030] Figure 9 is a bottom perspective view of the tensioning mechanism of the backrest assembly.

[0031] Figure 10 is a cross-sectional view of the tensioning mechanism of the backrest assembly taken along line 10-10 of Figure 8 .

[0032] Figure 11 is a front perspective view of the sliding mechanism of the backrest assembly.

[0033] Figure 12 is an exploded front perspective view of the sliding mechanism of the backrest assembly.

[0034] Figure 13 is a rear perspective view of the sliding mechanism of the backrest assembly.

[0035] Figure 14 is an exploded rear perspective view of the sliding mechanism of the backrest assembly.

[0036] Figure 15 is another rear perspective view of the sliding mechanism of the backrest assembly.

[0037] Figure 16 is a cross-sectional view of the sliding assembly taken along line 16-16 of Figure 11 .

[0038] Figure 17 is a cross-sectional view of the backrest assembly taken along line 17-17 of Figure 1 .

[0039] Figure 18 is a front perspective view of the handle.

[0040] Figure 19 is a rear perspective view of the handle.

[0041] Figure 20is a first perspective view of the cam.

[0042] Figure 21 is a second perspective view of the cam.

[0043] Figure 22 is a rear perspective view of the cam assembled on the handle.

[0044] Figure 23 is an exploded rear perspective view of the cam assembled on the handle.

[0045] Figure 24 is a cross-sectional view of a part of the backplate assembly with the backplate and the sliding mechanism cover omitted.

[0046] Figure 25 is another cross-sectional view of a part of the backplate assembly with the backplate and the sliding mechanism cover omitted.

[0047] Figure 26 is yet another cross-sectional view of a part of the backplate assembly with the backplate and the sliding mechanism cover omitted.

[0048] Figure 27 is a side view of a part of the backplate assembly with the backplate omitted, showing the backplate tension adjustment mechanism in the first position.

[0049] Figure 28 is a side view of a part of the backplate assembly with the backplate omitted, showing the backplate tension adjustment mechanism in the second position. Detailed Description

[0050] Reference Figure 1-7, the saw apparatus 1 includes a saw table top surface 2 and a fence assembly 30 which is supported on the saw apparatus 1 such that the fence 32 overlies the saw table top surface 2 and extends parallel to the cutting blade 8 of the saw apparatus 1. The saw apparatus 1 shown in the drawings is, for example, a table saw, although in other embodiments the saw apparatus 1 may be configured as other types of cutting tools, where the fence assembly is used to position a workpiece (not shown) relative to the blade 8 on a surface. The saw table top surface 2 is a saw table or cabinet structure (not shown) and defines a planar working surface 5 for supporting the workpiece. The saw table top surface 2 includes an opening 6. The blade 8 of the saw apparatus 1 (such as a circular saw blade) projects through the opening 6, and an insert 9 is placed in the opening 6 between the blade and the working surface 5. A motor (not shown) is placed inside the cabinet of the saw apparatus 1 and is configured such that the blade 8 rotates within the opening 6. The saw table top surface 2 has a pair of tracks 20, 22 which are configured to orient the fence assembly 30 relative to the blade when disposed on the saw table top surface 2. The fence assembly 30 includes a fence 32, a sliding mechanism 52 at a first end 34 of the fence 32, and a tensioning mechanism 82 at a second end 36 of the fence 32. The fence assembly 30 includes a handle 140 which pivots between a locked position and a released position, in the locked position the fence assembly 30 is fixed relative to the saw table top surface 2, and in the released position the fence assembly 30 is free to slide relative to the saw table top surface 2 along the tracks 20, 22. The handle 140 is supported on the sliding mechanism 52 via a cam 200. The fence assembly 30 also includes a link in the form of a tensioning member 120 which extends between the handle 140 and the tensioning mechanism 82. The cam 200 is part of a fence tensioning adjustment mechanism 190 which is configured to adjust the tension of the tensioning member 120. The fence assembly 30 includes a fence tensioning adjustment mechanism 190 which will be described in detail below.

[0051] The pair of tracks 20, 22 are configured to support the fence assembly 30 relative to the saw table top surface 2 and include a first track 20 and a second track 22. The first track 20 is located on one edge (such as a front edge) of the saw table top surface 2, and the second track 22 is located on an opposite edge (such as a rear edge) of the saw table top surface 2. In some embodiments, the tracks 20, 22 are integrally formed with the saw table top surface 2. In other embodiments, the tracks 20, 22 are formed as separate components, each being coupled to the saw table top surface 2 in place. The tracks 20, 22 are made of a rigid material such as metal or plastic. The first and second tracks 20, 22 have the same shape, and the shape of the tracks 20, 22 is such that the fence assembly 30 can be easily attached to and removed from them. The shape of the tracks 20, 22 also allows the fence assembly 30 to slide across the working surface 5 of the saw table top surface 2 for positioning by the user of the saw apparatus 1.

[0052] In the illustrated embodiment, the tracks 20, 22 have continuous outer surfaces such that the outer surfaces are formed without grooves or cavities as in conventionally known tracks. The outer surface includes a planar upper surface 24 for supporting the weight of the backstop assembly 30 and a planar lateral surface 26 to which the backstop assembly 30 is clamped to attach the backstop assembly 30 to the top surface 2 of the saw table ( Figure 3 ). The upper surface 24 is oriented generally parallel to the working surface 5 of the saw table. The lateral surface 26 in some embodiments is oriented generally orthogonal to the cutting direction 10, although in other embodiments the lateral surface 26 has a negative angle. As used herein, a lateral surface having a negative angle means that the lateral surface 26 has a planar orientation that exerts a downward force on the mating surface of the backstop assembly 30 when the backstop assembly 30 is disposed on the tracks 20, 22 of the top surface 2 of the saw table. The downward force exerted is configured to cause other surfaces of the backstop assembly 30 to be pushed downward against other surfaces of the saw table top 2 and the tracks 20, 22. The interior region of the tracks 20, 22 can be solid (as shown), hollow, or include any structure that improves the manufacturability, strength, and / or durability of the tracks. The tracks 20, 22 extend across the width of the saw table top 2 and define a guide axis 28 that is generally perpendicular to the cutting direction 10 of the blade 8. The backstop assembly 30 can be positioned relative to the blade 8 along the guide axis 28.

[0053] The backstop 32 ( Figure 7 is configured to guide a workpiece on the saw table top 2 and to position the sliding mechanism 52 and the tensioning mechanism 82 relative to each other. The backstop 32 is formed by a channel member or profile that in some embodiments defines an internal space for receiving or positioning other elements of the backstop assembly. For example, in some embodiments, the backstop is a hollow aluminum extrusion. The backstop 32 includes side portions 44, 46. The side portion 44 facing the blade 8 defines a generally planar guide surface for guiding the workpiece. When the backstop assembly 30 is accurately positioned relative to the blade 8, the side portion 44 provides a planar guide surface that is generally parallel to the cutting direction 10 of the blade to provide an accurate cut of the workpiece. In use, the workpiece rests on the saw table working surface 5 while abutting the guide surface, such as the side portion 44. The workpiece is cut by advancing the workpiece against the blade 8, which includes sliding the workpiece on the saw table working surface 5 and along the side portion 44.

[0054] Reference Figure 4 and Figure 8-10, the tensioning mechanism 82 cooperates with the sliding mechanism 52 and the handle 140 to apply tension to the tensioning member 120, which causes the backrest assembly 30 to be clamped to the top surface 2 of the saw table. The tensioning mechanism 82 includes a rear housing 84 fixed to the second end 36 of the backrest and a rod 100 that is pivotally attached to the rear housing 84 at its first end 102 via a rod pivot pin 108. In addition, the tensioning mechanism includes a wheel 114 that is rotatably fixed to the second end 104 of the rod 100, where the second end 104 is opposite the first end 102 of the rod.

[0055] The rod 100 is a rigid structure having a rectangular cross-section and also includes a rod opening 110 that receives the tensioning member 120. The rod opening 110 is generally positioned midway between the first and second ends 102, 104 of the rod. The tensioning member 120 is coupled to the rod 100 via a pivot pin 109 that extends through the rod 100 at a location corresponding to the rod opening 110.

[0056] The wheel 114 is fixed to the second end 104 of the rod so as to rotate about a wheel rotation axis 118 provided by a fastener 116 screwed into the rod 100. The wheel rotation axis 118 is parallel to the longitudinal axis 105 of the rod, where the rod longitudinal axis 105 extends between the first and second ends 102, 104 of the rod. In this configuration, when the backrest assembly 30 moves along the guide axis 28, the wheel 114 is oriented to rollingly contact the lateral surface 26 of the track 22. As Figure 4 shown, when viewed in a plane passing through and aligned with the wheel rotation axis 118, the wheel 114 has a spherical profile 119. The spherical profile 119 allows for freedom in the angular orientation of the wheel rotation axis 118 relative to the contact angle of the tracks 20, 22 to achieve linear rolling during movement of the backrest assembly 30 along the guide axis 28.

[0057] The rear housing 84 is configured to cover the rear end face 39 of the back plate 32. The rear housing 84 includes a cap portion 86 that closes the rear end face 39 of the back plate 32 and a guide block portion 88 that projects from the cap portion 86 toward the top surface 2 of the saw table and is configured to be supported on and slide relative to the upper surface 24 of the rear rail 22. Additionally, the rear housing 84 includes a housing stop portion 90 that depends from the cap portion 86. The housing stop portion 90 faces and is spaced from the lateral surface 26 of the rear rail. Additionally, a wheel 114 is disposed between the housing stop portion 90 and the rear lateral surface 26. Although there is sufficient space between the wheel 114 and the housing stop portion 90 for the wheel 114 to rotate freely about the wheel axis of rotation 118, the housing stop portion 90 limits the range of movement of the wheel 114 away from the rear lateral surface 26. The rear housing 84 includes a central through opening 92 that is defined in both the cap portion 86 and the guide block portion 88. The central through opening 92 is shaped and sized to permit the rod 100 to pivot through an arcuate length defined between the lateral surface 26 of the rear rail and the housing stop portion 90.

[0058] The guide block portion 88 of the rear housing 84 is positioned adjacent the second end 36 of the back plate 32 at the lower portion of the back plate 32. The guide block portion 88 projects inwardly from the cap portion 86 and has a planar lower surface 89 that is oriented generally parallel to the upper surface 24 of the rail 22. In the illustrated embodiment, the guide block portion 88 is configured to support the weight of the back plate assembly 30 on the rail 22 and to provide a small resistance to movement as the back plate assembly 30 moves along the guide axis 28. In other embodiments, the lower surface of the back plate 32 may support the weight of the back plate assembly 30 on the top surface 2 of the saw table and provide a small resistance to movement as the back plate assembly 30 moves along the guide axis 28.

[0059] Reference Figure 5 and Figure 11-16 FIGS., the sliding mechanism 52 includes a front housing 54 disposed at the first end 34 of the back plate and a cap 51 adjacent the front end face 38 of the back plate 32. The cap 51 includes an elongated slot 53 that receives and permits rotational movement of the handle 140 relative to the cap 51 and the sliding mechanism 52.

[0060] The front housing 54 is a rigid structure that has a T-shaped profile when viewed facing the top surface 2 of the saw table. The front housing 54 includes a body portion 56 and a flange portion 58. The body portion 56 is elongated in a direction parallel to the cutting direction 10 and is disposed within the hollow interior 48 of the fence 32. Specifically, the body portion 56 is shaped and sized to be received in the fence hollow interior 48 with a clearance fit and is coupled to the first end 34 of the fence 32 by using fasteners 65. Additionally, the side surfaces of the body portion 56 include grooves 66 that extend in a direction parallel to the cutting direction 10 and are open at each end 67, 68 of the body portion 56. The grooves 66 provide a passage for receiving the tension member 120 ( Figure 16 ). The end 68 of the body portion closest to the front rail 20 includes a circular cutout 64 that rotatably supports the fence tension adjustment mechanism 190, as further discussed below.

[0061] The flange portion 58 is disposed at the end 68 of the body portion 56 closest to the first end 34 of the fence. The flange portion 58 extends integrally from the surface of the body portion 56 facing the top surface of the saw table and extends bilaterally from the body portion 56 along the guide axis 28. The flange portion 58 includes rail-facing surfaces 69, 70 that are shaped and sized to face and engage the upper surface 24 and the lateral surface 26 of the first rail 20. For example, the flange portion 58 has a planar lower surface 69 and a planar lateral surface 70 adjacent to the lower surface 69. The lower surface 69 of the flange portion 58 is oriented substantially parallel to the upper surfaces 24 of the rails 20, 22. The orientation of the lateral surface 70 of the flange portion 58 substantially corresponds to the orientation of the lateral surfaces 26 of the rails 20, 22. In use, when the handle 140 is in the locked position, the body portion 56 and the flange portion 58 are fixed relative to the fence 32 so as to establish the alignment of the fence 32 relative to the blade via the sliding mechanism 52.

[0062] Both of the rail-facing surfaces 69, 70 include a pair of sliding contacts 60 that are laterally spaced apart bilaterally from the fence 32 along the guide axis 28. In the illustrated embodiment, the sliding contacts 60 are positioned near the ends of each of the rail-facing surfaces 69, 70. However, in other embodiments, the sliding contacts 60 may be positioned inwardly from the ends of the rail-facing surfaces 69, 70 or at other positions suitable to facilitate the sliding movement of the flange portion 58 along the first rail 20.

[0063] In the illustrated embodiment, the sliding contact 60 is formed separately from the flange portion 58 and is directly attached to the flange portion 58 by a fastener, adhesive, etc. The sliding contact 60 can be formed of a polymeric material such as ultra-high molecular weight polyethylene (UHMW) or Delrin®. In other embodiments, the sliding contact 60 is defined by the flange portion 58 such that the sliding contact is integrally formed by the material of the flange portion 58. Pairs of sliding contacts 60 establish two different electrical contacts between the corresponding tracks 20, 22 of the fence assembly 30 and the top surface 2 of the saw table to assist in aligning the fence assembly 30 relative to the blade. The sliding mechanism 52 is positioned in front of the top surface 2 of the saw table such that two pairs of sliding contacts 60 cooperate with the track 20 closest to the user of the saw apparatus 1.

[0064] Reference Figure 3-5 , the tension member 120 is an elongate rigid rod that operatively couples the sliding mechanism 52 to the tensioning mechanism 82. In the illustrated embodiment, the tension member 120 has a rectangular cross-sectional shape and is uniform along its length dimension. The tension member 120 has a first end 124 that is connected to the handle 140 via a pivot pin 160. The pivot pin 160 defines the axis of rotation of the first end 124 of the tension member relative to the handle 140. The axis of rotation is hereinafter referred to as the tension member connection axis 132, as discussed further below. The tension member 120 has a second end 126 opposite the first end 124. The second end 126 of the tension member includes an elongate through-hole (e.g., slot) 128 that receives the pivot pin 109 whereby the second end 126 of the tension member is pivotally coupled to the rod 100. In use, the tension member 120 is disposed within the fence 32 and allows tension to be transferred from the sliding mechanism 52 to the tensioning mechanism 82 in certain positions of the handle 140, as discussed more specifically below.

[0065] Reference Figure 5 , Figure 18-19 and Figure 22-23 , the handle 140 is supported on the front housing 54 via a cam 200. The handle 140 includes a first end 142 of the handle that is coupled to the tension member 120, a second end 144 of the handle opposite the first end 142, and an intermediate portion 146 of the handle disposed between the first and second ends 142, 144 of the handle. When the handle 140 is viewed in a direction perpendicular to the guide axis 28, the second end 144 of the handle is wider relative to the first end 142 of the handle and the intermediate portion 146 of the handle. The enlarged second end 144 of the handle is grasped by the user during operation of the handle 140 and has a rectangular shape that includes an outer surface 145 that is generally perpendicular to the side portions 44, 46 of the fence. The handle 140 includes a longitudinal axis 151 that extends through the second end 144 of the handle and the intermediate portion 146 of the handle and is parallel to the outer surface 145 of the second end 144 of the handle.

[0066] When the handle 140 is viewed in a direction parallel to the guide axis 28, it can be seen that the first end 142 of the handle is offset towards the backing plate 32 relative to the middle portion and the second ends 146, 144 of the handle. The first end 142 of the handle has a disk shape with planar side surfaces 147, 149 that are generally parallel to the side portions 44, 46 of the backing plate. Thus, when the handle 140 is viewed in a direction parallel to the guide axis 28, the first end 142 of the handle has a circular profile 148. In addition, the first end 142 of the handle includes a channel 150 that is open along the circular profile 148. The channel 150 opens towards the backing plate 32 and extends in a direction perpendicular to the guide axis 28. The channel 150 is shaped and sized to receive the first end 124 of the tension member and to allow the tension member 120 to rotate freely relative to the handle 140 regardless of the position of the handle 140. To this end, the tension member 120 is fixed to the first end 142 of the handle via a pivot pin 160 that bridges the channel 150.

[0067] The handle 140 includes a cylindrical shaft 152 that extends integrally and bilaterally from the side surfaces 147, 149 of the first end 142 of the handle. The shaft 152 is centered within the circular profile 148 defined by the first end 142 of the handle (e.g., the profile of the shaft 152 is concentric with the profile of the first end 142 of the handle). The shaft 152 has a shaft diameter d1 that is smaller than the diameter d2 of the first end 142 of the handle, such that a shoulder 154 for receiving the cam 200 is provided on the first end 142 of the handle. The shaft 152 has an outer or circumferential surface 156 that is supported on the inner bearing surface 208 of the cam 200 for rotation about the handle rotation axis 158, as discussed below. The handle rotation axis 158 is offset from the tension member connection axis 132 defined by the pivot pin 160. In the illustrated embodiment, the rotation axis 158 is closer to the backing plate than the tension member connection axis 132.

[0068] The handle 140 also includes a groove 164 formed in the surface 166 of the middle portion 146 of the handle that faces the backing plate. The groove 164 is shaped and sized to receive the dial 222 of the cam 200, as discussed below. In addition, a blind opening 168 is provided in the groove 164. The blind opening 168 is configured to engage an adjustment screw 240, as discussed below.

[0069] The handle 140 is operatively coupled to the front housing 54 of the sliding mechanism 52 via the cam 200, such that the handle 140 rotates about the handle rotation axis 158 relative to the front housing 54 between a first locked position (shown using solid lines in Figure 5 and a second released position (shown using dashed lines in Figure 5 .

[0070] In the first position, the handle longitudinal axis 151 is oriented at a first angle θ1 relative to the front housing 54. In the illustrated embodiment, when the handle 140 is at the first angle θ1 relative to the front housing 54, the handle longitudinal axis 151 is oriented substantially vertically, where the term "substantially vertical" means that the first angle θ1 is within plus or minus (+ / -) five degrees of vertical.

[0071] In the first position, the tension member connection axis 132 is positioned outward relative to the handle rotation axis 158 (e.g., further away from the back plate 32).

[0072] In the first position, a first tension is applied by the tension member 120 to the rod 100 of the tensioning mechanism 82. The first tension is sufficient to pull the wheel 114 against the rear track 22. Additionally, the tension member 120 subjects the sliding mechanism 52 to a counterforce or reaction force, where the flange portion 58 is pulled against the front track 20 and generates a vertical frictional force, whereby the tensioning mechanism 82 creates a clamping force between the wheel 114 and the pair of sliding contacts 60 on the saw table top surface 2. The clamping force applies sufficient force to secure the position of the back plate assembly 30 along the guide axis 28. In some embodiments, the clamping force is "sufficient force" if the back plate assembly 30 can resist movement when a side load of at least 30 pounds is applied in the direction of the guide axis 28.

[0073] In the second position, the handle longitudinal axis 151 is oriented at a second angle θ2 relative to the front housing 54. When the handle 140 is at the second angle θ2 relative to the front housing 54, the handle longitudinal axis 151 is oriented within a range of 45 to 90 degrees relative to vertical. For example, in the illustrated embodiment, the second angle θ2 is approximately 70 degrees from vertical.

[0074] As the handle 140 rotates from the first position to the second position, the tension member connection axis 132 moves generally upward (e.g., away from the saw table top surface 2) and inward (e.g., toward the back plate 32). In the illustrated embodiment, when the handle 140 is in the second position, the tension member connection axis 132 and the handle rotation axis 158 are located at approximately the same distance from the back plate 32. Since the tension member connection axis 132 is moved closer to the back plate 32, the tension force applied by the tension member 120 to the tensioning and sliding mechanisms is reduced relative to the tension force applied in the first position. More specifically, in the second position, the tension is reduced sufficiently to allow the back plate assembly to move easily along the tracks 20, 22, thereby enabling adjustment of the position of the back plate assembly 30 relative to the saw table top surface 2.

[0075] Reference Figure 5 、 Figure 12 、 Figure 14 and Figure 20-28, the backrest assembly 30 includes a backrest tension adjustment mechanism 190 configured to allow a user to finely adjust the backrest locking force (e.g., the amount of tension applied by the tension member 120 to the sliding mechanism 52 and the tension adjustment mechanism 82) when the handle is in the first position. Advantageously, the backrest tension adjustment mechanism 190 allows a user to compensate for, for example, cable stretching, wear, or excessive tension due to the accumulation of tolerances during manufacturing. The backrest tension adjustment mechanism 190 adjusts the effective length of the tension member 120 by increasing or decreasing the effective length. This adjustability allows a user to achieve an optimal balance between the locked backrest resistance and the force the user applies to the handle 140 to change the handle position.

[0076] The backrest tension adjustment mechanism 190 includes a cam 200 that supports the rotation of the handle 140 relative to the front housing 54 and an adjustment screw 240 that secures the cam 200 to the front housing.

[0077] The cam 200 is an assembly composed of a first annular member 202 and a second annular member 204. The first annular member 202 supports the shaft 152 on one side surface 147 of the first end 142 of the handle, and the second annular member 204 supports the shaft 152 on the other side surface 149 of the first end 142 of the handle. The first annular member 202 is separated from the second annular member 204 to allow the assembly to carry the shaft 152, and in use, the first annular member 202 is keyed into the second annular member 204 to rotate in unison with the second annular member 204.

[0078] Each of the first and second annular members 202, 204 includes an inner edge that serves as an inner bearing surface 208 rotatably supporting the outer surface 156 of the shaft. Each of the first and second annular members 202, 204 includes an outer edge that serves as an outer bearing surface 210 rotatably supported on the circular cutout 64 of the front housing 54. The outer bearing surface 210 has a circular profile and is centered on the rotation axis 212 of the cam 200. The inner bearing surface 208 has a circular profile, is eccentric with respect to the outer bearing surface 210, and is concentric with the handle rotation axis 158.

[0079] The first annular member 202 includes a planar first handle-facing surface 203 that extends between the inner and outer bearing surfaces 208, 210 of the first annular member 202. When the cam 200 is assembled with the handle 140, the first handle-facing surface 203 abuts the first side surface 147 of the first end 142 of the handle. In addition, the first annular member 202 includes a first protrusion 216 that projects from the first handle-facing surface 203 toward the second annular member 204. The first protrusion 216 has a curved and outward-facing surface that is flush with a portion of the outer bearing surface 210 of the first annular member 202.

[0080] Similarly, the second annular member 204 includes a planar second handle-facing surface 205 that extends between the inner and outer bearing surfaces 208, 210 of the second annular member 204. When the cam 200 is assembled with the handle 140, the second handle-facing surface 205 abuts a second side surface 149 of the first end 142 of the handle. Additionally, the second annular member 204 includes a second protrusion 218 that projects from the second handle-facing surface 205 toward the first annular member 202. The second protrusion 218 has a curved outer-facing surface that is flush with a portion of the outer bearing surface 210 of the second annular member 204.

[0081] The second protrusion 218 includes a notch 220 that opens toward the first annular member 202 and is shaped and sized to receive the first protrusion 216. When the cam 200 is assembled with the handle 140, the first protrusion is placed in the notch 220, whereby the first annular member 202 is keyed into the second annular member 204. The second protrusion 218 also includes a pendant leg that serves as a dial 222. The dial 222 extends radially outward from the second protrusion 218 (e.g., away from the first end 142 of the handle). When the cam 200 is assembled with the handle 140, the dial 222 faces the middle portion 146 of the handle and is aligned with the groove 164. The dial 222 includes a through-opening 224 that is configured to receive an adjustment screw 240 that passes therethrough. More specifically, the through-opening 224 slidably engages the adjustment screw 240 such that the dial 222 moves in unison with the axial position of the adjustment screw 240.

[0082] The cam 200 is formed of a low-friction material to facilitate rotation of the cam 200 relative to the front housing 54 and to facilitate rotation of the shaft 152 relative to the inner bearing surfaces 208, 208 of the cam. For example, in some embodiments, the cam 200 is formed of ultra-high molecular weight (UHMW) polyethylene (PE).

[0083] The adjustment screw 240 includes a head 242 and a threaded shank 244 that extends from one end of the head 242. The threads of the shank 244 are shaped and sized to engage corresponding threads disposed in the blind opening 168 that is located in the groove 164 of the middle portion 146 of the handle. In this position, the adjustment screw 240 is located below the cam axis of the wheel 212.

[0084] The adjustment screw 240 is configured to adjust the rotational orientation of the cam 200 relative to the front housing 54. Specifically, adjusting the position of the adjustment screw 240 relative to the front housing 54 (e.g., via rotation of the adjustment screw 240 relative to the opening 168) causes movement of the dial 222 relative to the front housing 54. In turn, the movement of the dial 222 causes the rotational orientation of the cam 200 relative to the front housing 54. In this regard, the cam 200 is rotatable relative to the front housing 54 via adjustment of the adjustment screw 240. Since the handle shaft 152 is eccentrically supported on the inner bearing surface 208 of the cam 200 relative to the cam rotation axis 212, a change in the rotational orientation of the cam 200 changes the position of the tension member connection axis 132 relative to the backplate 32. In other words, a change in the rotational orientation of the cam 200 causes an increase or decrease in the effective length of the tension member 120.

[0085] Decreasing the effective length of the tension member 120 causes an increase in the tension applied by the tension member 120. This is achieved by rotating the adjustment screw 240 into the threaded opening 168, which causes the dial 222 to move closer to the front housing 54 ( Figure 27 ). When the handle 140 is in the first locked position, the increased tension is associated with an increased locking force at the rear of the backplate assembly 30. The increased tension increases the effective resistance on the handle 140 and requires the user to apply an increased input force to operate the handle 140. This adjustment can be made to account for cable stretch, wear, etc. within the backplate assembly 30.

[0086] Increasing the effective length of the tension member 120 has the opposite effect. That is, the increased effective tension length decreases the tension applied by the tension member 120. This is achieved by rotating the adjustment screw 240 out of the threaded opening 168, which causes the dial 222 to move away from the front housing 54 ( Figure 24 and Figure 28 ). This results in a decreased locking force at the rear track 22, but also results in a decreased input force from the user to operate the handle 140. This adjustment can be made, for example, when the tension adjustment has been made overly and the force required to ultimately operate the handle 140 is unreasonable for the user.

[0087] The cam 200 is capable of rotating within the range of at least 5 degrees and not exceeding 90 degrees in the backrest assembly 30. The first end 124 of the tension member is connected to a position inside the cam 200 with a degree of rotational freedom but eccentric to the cam axis of the wheel 212. Thus, the rotation of the cam 200 serves as a lever function to reposition the tension member connection axis 132. The greater the distance from the tension member connection axis 132 to the cam axis of the wheel 212, the greater the change in position for a given degree of adjustment angle. A greater degree of adjustment angle also results in a greater change in position. The simple machine lever is achieved around a pivot point, which is the cam axis of the wheel 212, and the two balance ends of the lever are the positions of the tension member connection axis 132 and the actuating point of the cam 200, for example, the position of the adjustment screw 240. As the distance between the position of the adjustment screw 240 and the tension member connection axis 132 increases, the force required to adjust the tension decreases. The position of the tension member connection axis 132 is important because the eccentric tension will result in a rotational moment on the adjustment member. The cam 200 is configured to support any moment caused by the tensile force.

[0088] Once the adjustment of the rotational orientation of the cam 200 relative to the front housing 54 has been made, the adjustment screw 240 is used to secure (e.g., fix) the cam 200 to the front housing 54 in the desired cam rotational orientation, and the handle 140 is capable of moving between a first handle position and a second handle position relative to the fixed cam 200.

[0089] Since the adjustment screw 240 is placed between the handle 140 and the front housing 54, the adjustment screw 240 is located behind the handle 140 when the backrest assembly 30 is observed by the user of the saw device 1. When the backrest assembly 30 is in the locked state and the tension is high, placing the adjustment screw 240 in this position prevents the adjustment of the cam rotational orientation. When the backrest assembly 30 is in the unlocked state and the handle 140 is in the second position, the adjustment screw 240 is exposed, allowing the adjustment of the cam rotational orientation and thus the adjustment of the tension of the tension member 120, as discussed below. In the unlocked state, the tension is much smaller and the adjustment is easier. This configuration allows the backrest tension adjustment mechanism 190 not to act under a large load and thus be more compact due to lower strength requirements.

[0090] Since the backrest tension adjustment mechanism 190 including the cam 200 and the adjustment screw 240 are placed on the front housing 54, a user standing in front of the saw device 1 can easily access the backrest tension adjustment mechanism 190. Moreover, the tension of the tension member 120 can be adjusted by using the backrest tension adjustment mechanism 190 without removing the backrest assembly 30 from the top of the saw table 2.

[0091] Although the tensioning member 120 is described herein as a rod, the tensioning member is not limited to this configuration. For example, in some embodiments, the tensioning member 120 can be a cable. The cable has the advantage of providing flexibility, which can accommodate bending due to friction and can maintain a favorable degree of freedom of the rotating member.

[0092] Although the top surface 2 of the saw table of the saw device 1 shown in the illustrated embodiment includes a pair of tracks 20, 22, the saw device 1 is not limited to this configuration. For example, in some embodiments, a saw device having only one track is contemplated. In these cases, locking can be achieved by clamping from the back side of one track.

[0093] Although the saw device 1 shown in the drawings is, for example, a table saw, the saw device is not limited to being a table saw. In other embodiments, the saw device can be, for example, a band saw, a saw blade, or other types of cutting tools where a rip fence or a fence assembly is used to position a workpiece on a surface relative to a blade or other cutting element.

[0094] Selective illustrative embodiments of a portable table saw and a fence assembly including a fence tensioning adjustment mechanism have been specifically described above. It should be understood that only the structures necessary to define certain features of the table saw and the fence assembly have been described here. Other conventional structures of the portable table saw and the fence assembly, as well as accessory and auxiliary components, are considered to be known and understood by those skilled in the art. Moreover, although working examples of the portable table saw and the fence assembly have been described above, the portable table saw and the fence assembly are not limited to the working examples described above, but rather various design changes can be made without departing from the portable table saw, the fence assembly, and / or the fence tensioning adjustment mechanism set forth in the claims.

Claims

1. A fence assembly configured to guide a workpiece relative to a blade of a saw device and supported for translation along a track relative to a working surface of the saw device, the fence assembly comprising: A fence including a first end of the fence and a second end of the fence opposite the first end of the fence; A sliding mechanism coupled to the first end of the fence and supported on a first track in the track; A tensioning mechanism coupled to the second end of the fence and supported on a second track in the track; A handle supported on the sliding mechanism via a cam, the handle being rotatable relative to the cam between a first position and a second position, in the first position the fence assembly being fixed relative to the track, and in the second position the fence assembly being movable relative to the track; And A tensioning member including a first end coupled to the handle, the tensioning member including a second end opposite the first end and coupled to the tensioning mechanism; Wherein the cam is rotatable relative to the sliding mechanism about a cam rotation axis, and rotation of the cam relative to the cam rotation axis provides adjustment of the tension applied by the tensioning member; Wherein the cam includes an outer bearing surface rotatably supported on a housing of the sliding mechanism and an inner bearing surface rotatably supporting the handle, wherein the inner bearing surface is eccentrically positioned relative to the outer bearing surface, and the tensioning member is coupled to the handle via a pivot pin, Rotation of the cam relative to the cam rotation axis changes the position of the pivot pin relative to the first end of the fence, and A change in the position of the pivot pin relative to the first end of the fence changes the tension applied by the tensioning member to the tensioning mechanism.

2. The fence assembly according to claim 1, wherein The handle is rotatable relative to the cam about a handle rotation axis, and The cam rotation axis is parallel to and spaced from the handle rotation axis.

3. The fence assembly according to claim 1, wherein The tensioning member has a first end connected to the handle via a pivot pin that defines a tensioning member connection axis, The handle is rotatable relative to the cam about a handle rotation axis, and The handle rotation axis is parallel to and spaced from the tensioning member connection axis.

4. The fence assembly according to claim 1, wherein the handle is rotatable between the first position and the second position, in the first position the tensioning member being under a first tension and the sliding mechanism and the tensioning mechanism being fixed relative to the track, and in the second position the tensioning member being under a second tension and the front housing and the rear housing being movable relative to the track, wherein the second tension is less than the first tension.

5. The fence assembly according to claim 1, wherein the tensioning member is a rod.

6. The fence assembly according to claim 1, wherein the cam includes An outer bearing surface rotatably supported on a housing of the sliding mechanism, and An inner bearing surface that rotatably supports the handle, wherein the inner bearing surface is eccentrically positioned relative to the outer bearing surface.

7. The backrest assembly according to claim 1, comprising a backrest tension adjustment mechanism configured to adjust the tension of the tension member, the backrest tension adjustment mechanism including a cam; and an adjustment screw coupled to the cam and engaging the housing, the adjustment screw being configured to adjust the rotational orientation of the cam relative to the housing.

8. The backrest assembly according to claim 7, wherein the cam is rotatable relative to the housing between a first cam rotational orientation and a second cam rotational orientation, in the first cam rotational orientation the tension member has a first tension, and in the second cam rotational orientation the tension member has a second tension, and the first tension is greater than the second tension.

9. The backrest assembly according to claim 7, wherein the adjustment screw is configured to fix the cam to the housing in a desired cam rotational orientation.

10. The backrest assembly according to claim 7, wherein the adjustment screw enables the cam to be rotatable relative to the front housing between a first cam rotational orientation and a second cam rotational orientation, in the first cam rotational orientation the tension member connection axis is at a first distance from one end of the backrest, and in the second cam rotational orientation the tension member connection axis is at a second distance from the end of the backrest, the first distance is different from the second distance, and the amount of tension provided in the tension member corresponds to the distance of the tension member connection axis from the end of the backrest.

11. The backrest assembly according to claim 7, wherein the handle obstructs access to the adjustment screw when the handle is in the first position, and the handle does not obstruct access to the adjustment screw when the handle is in the second position.

12. The backrest assembly according to claim 1, wherein the cam includes a first annular member and a second annular member, the second annular member is separable from the first annular member, and the second annular member is keyed into the first annular member to rotate in unison with the first annular member.

13. The backrest assembly according to claim 1, wherein the cam includes a first annular member and a second annular member, the first annular member includes a first inner edge, a first outer edge surrounding the first inner edge, a first handle-facing surface extending between the first outer edge and the first inner edge, and a first protrusion protruding from the first handle-facing surface, and the second annular member includes a second inner edge, a second outer edge surrounding the second inner edge, a second handle-facing surface extending between the second outer edge and the second inner edge, and a second protrusion protruding from the second handle-facing surface, the second protrusion including a groove that receives and engages the first protrusion.

14. The backrest assembly according to claim 13, wherein the adjusting screw is coupled to the cam and engages the sliding mechanism, and the adjusting screw is configured to adjust the rotational orientation of the cam relative to the sliding mechanism.

15. The backrest assembly according to claim 13, wherein the handle includes a cylindrical shaft projecting bilaterally from a first end of the handle, the first annular member is disposed on one side of the handle and a first portion of the shaft is supported on the first inner edge, and the second annular member is disposed on the other side of the handle and a second portion of the shaft is supported on the second inner edge.

16. A saw device including a backrest assembly, the backrest assembly being supported relative to a working surface of the saw device via a first rail and a second rail of the saw device, the backrest assembly comprising: a backrest; a sliding mechanism disposed at a first end of the backrest, the sliding mechanism including a housing configured to engage the first rail; a tensioning mechanism disposed at a second end of the backrest, the tensioning mechanism being configured to engage the second rail; a handle supported on the sliding mechanism, the handle being movable relative to the sliding mechanism between a first position and a second position; a tensioning member including a first end coupled to the first end of the handle and a second end coupled to the tensioning mechanism; and a backrest tensioning adjustment mechanism configured to adjust the tension of the tensioning member, wherein: when the handle is in the first position, a first tension is applied by the tensioning member to the tensioning mechanism, and when the handle is in the second position, a second tension is applied by the tensioning member to the tensioning mechanism, the second tension being less than the first tension, the backrest tensioning adjustment mechanism includes a cam supported on the sliding mechanism for rotation about a cam rotation axis, the cam being configured to support the handle for rotation about a handle rotation axis parallel to and spaced from the cam rotation axis, and an adjusting screw passing through an opening in the cam and engaging the housing, the adjusting screw being configured to adjust the rotational position of the cam relative to the housing.

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