Reciprocating saw

Abstract

A reciprocating saw includes a spindle assembly having a frame and a spindle reciprocating along a spindle axis between a rear dead center (BDC) and a front dead center (FDC). The spindle includes a blade connector defining a connection axis. The saw includes a track plate, an eccentric drive member, and a follower that engages a cam surface on the track plate to pivot the frame about a pivot axis. The cam surface includes a high frequency section occupying a periphery of the cam surface less than 180 degrees. Displacement of the connection axis with respect to a direction perpendicular to the spindle axis is zero at the FDC. A total displacement of the connection axis in a direction perpendicular to the spindle axis occurs during a forward stroke and a reverse stroke. The high frequency section is configured to displace the connection axis between 80% and 100% of the total displacement.

Description

[0001] Cross Reference to Related Applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 737,941, filed December 23, 2024, U.S. Provisional Patent Application No. 63 / 715,895, filed November 4, 2024, and U.S. Provisional Patent Application No. 63 / 633,171, filed April 12, 2024, the entire contents of all of which are incorporated by reference herein. TECHNICAL FIELD

[0003] The present utility model relates to power tools, and more particularly to a reciprocating saw. BACKGROUND

[0004] Power tools include different types of drive mechanisms to perform work. Power tools with reciprocating drive mechanisms typically include counterweights to balance the force generated by the output element (e.g., a saw blade) during reciprocating motion. Power tools with orbital drive mechanisms typically include a tilt surface for pivoting the output element. SUMMARY

[0005] In one aspect, the utility model provides a kind of reciprocating saw, which includes shell, electric motor and main shaft assembly positioned in shell and having motor output shaft rotatable about motor axis.The main shaft assembly includes main shaft frame pivotably coupled to the shell about a pivot axis defined by a pivot joint, and a main shaft supported for reciprocating motion within the main shaft frame along a main shaft axis oriented perpendicular to the pivot axis.The main shaft reciprocates along the main shaft axis between a back dead center (BDC) position and a front dead center (FDC) position.The main shaft includes a blade connection portion configured to secure a blade.The blade connection portion defines a blade connection axis parallel to the pivot axis.The reciprocating saw includes a track plate configured to convert torque from the motor output shaft to reciprocating motion of the main shaft.The track plate includes a cam surface about a rotation axis of the track plate.The reciprocating saw includes an eccentric drive member coupled to the track plate for co-rotation therewith.The eccentric drive member has an eccentric portion offset from the rotation axis of the track plate.The eccentric portion is coupled to the main shaft to cause reciprocating motion of the main shaft in response to rotation of the eccentric drive member and the track plate.The reciprocating saw includes a follower coupled to the main shaft assembly and engaged with the cam surface on the track plate to cause the main shaft frame to pivot about the pivot axis in response to rotation of the track plate, thereby causing orbital motion of the main shaft.The cam surface includes a high-frequency segment occupying less than 180 degrees of a circumference of the cam surface.Displacement of the blade connection axis in a direction perpendicular to the main shaft axis is zero when the main shaft is in the FDC position.Total displacement of the blade connection axis in a direction perpendicular to the main shaft axis occurs during a forward stroke as the main shaft travels from the BDC position to the FDC position and during a reverse stroke as the main shaft travels from the FDC position to the BDC position.The high-frequency segment is configured to displace the blade connection axis between 80% and 100% of the total displacement.

[0006] In another aspect, the utility model provides a kind of reciprocating saw, which includes shell, electric motor positioned in shell and with the motor output shaft rotatable about motor axis and main shaft assembly.The main shaft assembly includes the main shaft frame pivotably coupled to shell about the pivot joint of the pivot axis, and the main shaft supported for reciprocating motion within the main shaft frame along the main shaft axis oriented perpendicular to the pivot axis.The main shaft reciprocates along the main shaft axis between a back dead center (BDC) position and a front dead center (FDC) position.The reciprocating saw includes track plate, which is configured to convert torque from the motor output shaft into reciprocating motion of the main shaft.The track plate includes cam surface about the rotation axis of the track plate.The reciprocating saw includes eccentric drive member, which is coupled to the track plate for co-rotation therewith.The eccentric drive member has eccentric portion offset from the rotation axis of the track plate and eccentric pin, which is coupled to the main shaft to cause reciprocating motion of the main shaft in response to rotation of the eccentric drive member and the track plate.The reciprocating saw includes follower, which is coupled to the main shaft assembly and engages the cam surface on the track plate to cause the main shaft frame to pivot about the pivot axis in response to rotation of the track plate, thereby causing orbital motion of the main shaft.The cam surface includes high-frequency section spanning the circumference of the cam surface between first point and second point.The cam surface includes low-frequency section spanning the remainder of the circumference of the cam surface.The main shaft defines forward stroke when moving from the BDC position to the FDC position, and reverse stroke when moving from the FDC position to the BDC position.At first rotational position of the track plate, the follower engages the first point.The eccentric pin is angularly offset from the first point at the first rotational position relative to the rotation axis at an included angle between -180 degrees and 180 degrees.

[0007] In another aspect, the utility model provides a kind of reciprocating saw, which includes shell and the electric motor in shell and with the motor output shaft that can rotate around motor axis.Reciprocating saw further includes main shaft assembly, main shaft assembly has the main shaft frame that is pivotally coupled to shell around pivot axis and the main shaft that is supported for reciprocating motion in main shaft frame along the main shaft axis that is oriented perpendicular to pivot axis.Reciprocating saw further includes drive mechanism, drive mechanism is configured to convert the torque from motor output shaft into the reciprocating motion of main shaft.Drive mechanism includes drive pinion that is coupled to rotate with motor output shaft and driven gear that is engaged with drive pinion and has cam surface around the rotation axis of driven gear.Drive mechanism further includes crankshaft that is coupled to driven gear to rotate with it.Crankshaft has first eccentric portion that is offset from the rotation axis of driven gear and second eccentric portion that is offset from the rotation axis of driven gear.First eccentric portion is coupled to main shaft to cause reciprocating motion of main shaft in response to the rotation of crankshaft and driven gear.Reciprocating saw further includes counterweight, which is coupled to second eccentric portion of crankshaft to receive reciprocating motion from it in response to the rotation of crankshaft and driven gear.Reciprocating saw further includes follower, which is coupled to main shaft assembly and engages with cam surface on driven gear to cause main shaft frame to pivot around pivot axis in response to the rotation of driven gear, thereby causing orbital motion of main shaft.Cam surface defines continuously sloped edge on the outer periphery of driven gear.Continuously sloped edge includes first section and second section.First section has first wave form, and second section has second wave form different from first wave form.

[0008] In another aspect, the utility model provides a kind of reciprocating saw, which includes shell, the electric motor in shell and with the motor output shaft that can rotate around motor axis and main shaft assembly.Main shaft assembly includes main shaft frame, which is pivotally coupled to shell around pivot joint that defines pivot axis.Main shaft assembly includes main shaft, which is supported for reciprocating motion in main shaft frame along the main shaft axis that is oriented perpendicular to pivot axis.Reciprocating saw includes transmission member, which is configured to receive torque from motor output shaft, such that transmission member rotates around rotation axis.Reciprocating saw includes eccentric drive member, which is coupled to transmission member to rotate with it.Eccentric drive member has eccentric portion that is offset from the rotation axis of transmission member.Eccentric portion is coupled to main shaft to cause reciprocating motion of main shaft in response to the rotation of eccentric drive member and transmission member around rotation axis.Reciprocating saw includes cam surface around the rotation axis of transmission member.Reciprocating saw includes follower, which is coupled to main shaft assembly and engages with cam surface to cause main shaft frame to pivot around pivot axis in response to the rotation of cam surface around rotation axis, thereby causing orbital motion of main shaft.Cam surface includes first section and second section, first section has first wave form, and second section has second wave form different from first wave form.

[0009] In another aspect, the utility model provides a kind of reciprocating saw, which includes shell, electric motor with the motor output shaft that can rotate around motor axis is positioned in shell and main shaft assembly.The main shaft assembly includes main shaft frame, and main shaft frame is pivotably coupled to shell around pivot joint that defines pivot axis.The main shaft assembly includes main shaft, and main shaft is supported for reciprocating motion within main shaft frame along main shaft axis that is oriented perpendicular to pivot axis.The reciprocating saw includes transmission member, and transmission member is configured to receive torque from motor output shaft, so that transmission member rotates around rotation axis.The reciprocating saw includes eccentric drive member, and eccentric drive member is coupled to transmission member to rotate with it, and eccentric drive member is offset from the rotation axis of transmission member by a distance greater than 0.625 inch and less than or equal to 0.75 inch.Eccentric drive member is coupled to main shaft to cause reciprocating motion of main shaft in response to the rotation of eccentric drive member and transmission member around rotation axis.The reciprocating saw includes cam surface around the rotation axis of transmission member.The reciprocating saw includes follower, and follower is coupled to main shaft assembly and engages with cam surface to cause main shaft frame to pivot around rotation axis in response to the rotation of cam surface around rotation axis, so that main shaft generates orbital motion.

[0010] In another aspect, the present invention provides a reciprocating saw comprising a housing, an electric motor positioned within the housing and having a motor output shaft rotatable about a motor axis, and a spindle assembly. The spindle assembly includes a spindle frame pivotally coupled to the housing about a pivot joint defining a pivot axis, and a spindle supported for reciprocating motion within the spindle frame along a spindle axis oriented perpendicular to the pivot axis. The spindle reciprocates between a rear dead center (BDC) position and a front dead center (FDC) position along the spindle axis. The spindle includes a saw blade connection portion configured to fix a saw blade. The saw blade connection portion defines a saw blade connection axis parallel to the pivot axis. The reciprocating saw includes a track plate configured to convert torque from the motor output shaft into reciprocating motion of the spindle. The track plate includes a cam surface about a rotation axis of the track plate. The reciprocating saw includes an eccentric drive member coupled to the track plate for rotation therewith. The eccentric drive member has an eccentric portion offset from the rotation axis of the track plate. An eccentric portion is coupled to the spindle to reciprocate the spindle in response to rotation of the eccentric drive member and the track plate. The reciprocating saw includes a follower coupled to the spindle assembly and engaging a cam surface on the track plate to pivot the spindle frame about a pivot axis in response to rotation of the track plate, thereby causing the spindle to orbit. The cam surface includes a high-frequency segment occupying less than 180 degrees of its circumference. When the spindle is in the FDC position, the displacement of the saw blade connecting axis in the direction perpendicular to the spindle axis is zero. The maximum positive displacement of the saw blade connecting axis in the direction perpendicular to the spindle axis occurs during the positive stroke of the spindle from the BDC position to the FDC position. The phase angle of the cam surface at the FDC position is 0 degrees. The phase angle of the cam surface at the BDC position is 180 degrees, and the phase angle of the cam surface at the maximum positive displacement is between 200 degrees and 280 degrees.

[0011] On the other hand, the present invention provides a reciprocating saw comprising a housing, an electric motor positioned within the housing and having a motor output shaft rotatable about a motor axis, and a spindle assembly. The spindle assembly includes a spindle frame pivotally coupled to the housing via a pivot joint about a defining pivot axis, and a spindle supported for reciprocating motion within the spindle frame along a spindle axis oriented perpendicular to the pivot axis. The reciprocating saw includes a transmission member configured to receive torque from the motor output shaft, causing the transmission member to rotate about a rotation axis. The reciprocating saw includes an eccentric drive member coupled to the transmission member for rotation therewith. The eccentric drive member includes an eccentric portion offset from the rotation axis of the transmission member. The eccentric portion is coupled to the spindle to cause the spindle to reciprocate in response to rotation of the eccentric drive member and the transmission member about the rotation axis. The reciprocating saw includes a cam surface about the rotation axis of the transmission member. The reciprocating saw includes a follower coupled to a spindle assembly and engaging a cam surface to pivot the spindle frame about a rotation axis in response to rotation of the cam surface about the rotation axis, thereby causing the spindle to move along a track. The cam surface includes a first segment and a second segment, the first segment defining a first average slope and the second segment defining a second average slope. The first average slope is greater than the second average slope.

[0012] Other features and aspects of this invention will become apparent from a careful reading of the following detailed description and accompanying drawings. Attached Figure Description

[0013] Figure 1 This is a side view of a reciprocating saw.

[0014] Figure 2A Is with Figure 1 A schematic diagram of the drive mechanism and spindle assembly used in a reciprocating saw.

[0015] Figure 2B Is with Figure 1 A schematic diagram of the drive mechanism and spindle assembly used in a reciprocating saw.

[0016] Figure 2C Is with Figure 1 The cross-section of the drive mechanism and spindle assembly used in reciprocating saws.

[0017] Figure 3 Is with Figure 2A and 2B The drive mechanism is used together, and the top view of the track plate is shown in the front dead center position.

[0018] Figure 4 It is along Figure 3 Section 4-4 is cut from the middle. Figure 3 A cross-sectional view of the track slab.

[0019] Figure 5 is a graph of the wave form of the cam surface of the orbital plate of Figure 3 .

[0020] Figure 6 is a top view of the orbital plate of Figure 3 in a first rotational position.

[0021] Figure 7 is a top view of the orbital plate of Figure 3 in a back dead center position.

[0022] Figure 8 is a top view of the orbital plate of Figure 3 in a second rotational position.

[0023] Figure 9 is a graph of the orthogonal dimension of the displacement of the blade connecting axis of the reciprocating saw of Figure 3 comparing the use of the orbital plate of Figure 1 .

[0024] Figure 10 is a graph of the orthogonal dimension of the displacement of the blade connecting axis of the reciprocating saw of Figure 9 comparing the use of the prior art orbital plate and the reciprocating saw.

[0025] Figure 11A is a side view of the reciprocating saw of Figure 3 with the orbital plate having Figure 1 during a reverse stroke.

[0026] Figure 11B is a side view of the reciprocating saw of Figure 3 with the orbital plate having Figure 1 during a forward stroke.

[0027] Figure 11C is a side view of the reciprocating saw of Figure 1 with the orbital plate of Figure 3 in an FDC position.

[0028] Figure 12 is a vibration graph of the reciprocating saw of Figure 3 using the orbital plate of Figure 10 and the prior art orbital plate.

[0029] Figure 13 is a graph of the average cutting duration using orbital plates having different included angles.

[0030] Figure 14 is a graph of the orthogonal dimension of the displacement of the blade connecting axis of the reciprocating saw of Figure 1 comparing the use of the orbital plate according to another embodiment.

[0031] Figure 15is a plot of the orthogonal dimension of the displacement of the saw blade connection axis of a reciprocating saw according to another embodiment using a rail plate Figure 1

[0032] Figure 16 is a plot of the orthogonal dimension of the displacement of the saw blade connection axis of a reciprocating saw according to another embodiment using a rail plate Figure 1

[0033] Figure 17 is a plot of the orthogonal dimension of the displacement of the saw blade connection axis of a reciprocating saw according to another embodiment using a rail plate Figure 1

[0034] Figure 18 is a plot of the orthogonal dimension of the displacement of the saw blade connection axis of a reciprocating saw according to another embodiment using a rail plate Figure 1

[0035] Figure 19 is a plot of the orthogonal dimension of the displacement of the saw blade connection axis of a reciprocating saw according to another embodiment using a rail plate Figure 1

[0036] Figure 20 is a plot of the orthogonal dimension of the displacement of the saw blade connection axis of a reciprocating saw according to another embodiment using a rail plate Figure 1

[0037] Figure 21 is a plot of the orthogonal dimension of the displacement of the saw blade connection axis of a reciprocating saw according to another embodiment using a rail plate Figure 3 Figure 1

[0038] Figure 22 is a plot of the main axis velocity of a reciprocating saw according to another embodiment using a rail plate Figure 3 Figure 1

[0039] Figure 23 is a plot modeling the average time to cut using a rail plate of Figure 3 Figure 10 Figure 1

[0040] Figure 24 is a side view of the reciprocating saw of Figure 1

[0041] Figure 25A is a side view of the reciprocating saw of Figure 1 ​​​​​​​​​​​​​​is a side view of a blade of a reciprocating saw having a stroke length of 1.25 inches at the FDC position before starting a cut.

[0042] Figure 25B is Figure 1 is a side view of a blade of a reciprocating saw having a stroke length of 1.25 inches at the BDC position after a reverse stroke.

[0043] Figure 25C is Figure 1 is a side view of a blade of a reciprocating saw having a stroke length of 1.25 inches at the FDC position after a forward stroke.

[0044] Figure 26A is Figure 1 is a side view of a blade of a reciprocating saw having a stroke length of 1.5 inches at the FDC position before starting a cut.

[0045] Figure 26B is Figure 1 is a side view of a blade of a reciprocating saw having a stroke length of 1.5 inches at the BDC position after a reverse stroke.

[0046] Figure 26C is Figure 1 is a side view of a blade of a reciprocating saw having a stroke length of 1.5 inches at the FDC position after a forward stroke.

[0047] Before any embodiments of the present application are explained in detail, it is to be understood that the application is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The application is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and not of limitation. DETAILED DESCRIPTION

[0048] Figure 1 An electric power tool (e.g., a reciprocating saw 100) operable to drive a blade 104 in an orbital cutting motion is shown. In the illustrated embodiment, the blade 104 is reciprocated along a linear axis or spindle axis Al while being pivoted about a pivot axis A2 Figure 2A The reciprocating saw 100 reciprocates the blade 104 through a fixed stroke length (e.g., 1.25 inches, 1.375 inches, 1.5 inches, etc.).

[0049] The reciprocating saw 100 includes a housing 108, an electric motor 112 positioned within the housing 108, and a drive mechanism 110A that receives torque from the motor 112 to drive the blade 104 in the above-described reciprocating and orbital cutting motions Figure 2A). The saw 100 also includes a handle 124 that covers a portion of the housing 108 and a D-shaped handle 128 located at a rear of the housing 108, both of which are grasped by a user during operation of the reciprocating saw 100. The handle 124 is made of a resilient material (e.g., rubber, silicone, etc.) and extends around a portion of the housing 108. The saw 100 further includes a trigger 130 (e.g., a variable speed trigger) on the handle 128 that is depressed by a user to activate the motor 112. A shoe 132 extends from the housing 108 to abut a workpiece 134 Figures 11A-11C ) during a cutting operation. The shoe 132 includes a slot 136 through which the blade 104 extends.

[0050] The saw 100 includes a battery receiver (not shown) located below the handle 128. The battery receiver is configured to receive a battery pack 144. The battery pack 144 can include any of a number of different nominal voltages (e.g., 12V, 18V, etc.) and can be configured to have any of a number of different chemistries (e.g., lithium-ion, nickel-cadmium, etc.). In other embodiments, the reciprocating saw 100 can include a power cord, which enables the motor 112 to be powered by an AC power source (e.g., a wall outlet, a portable generator, etc.).

[0051] Referring to Figure 2A , the motor 112 includes a motor output shaft 148 that defines a motor axis A3, which in some cases is parallel to the spindle axis Al. The drive mechanism 110A includes a drive pinion 156, a driven gear 160 (e.g., a transmission member), and a crankshaft 164. The drive pinion 156 is coupled to co-rotate with the motor output shaft 148 and is in meshing engagement with the driven gear 160. In some embodiments, the drive pinion 156 and the driven gear 160 can be spiral bevel gears, but can alternatively be any other type of meshing gear set (e.g., straight bevel gears, etc.).

[0052] The driven gear 160 includes a first side 176 and a second side 180 opposite the first side 176. The first side 176 includes a second plurality of teeth 184 that mesh with the first plurality of teeth 172 of the drive pinion 156. The driven gear 160 is rotatably supported by an intermediate shaft 188, which in turn is supported within the housing 108 by a stacked roller member 192 (e.g., a roller bearing). The bearing 192 supports the intermediate shaft 188 for rotation about an intermediate shaft axis A4 (also the axis of rotation of the driven gear 160) that is perpendicular to the motor axis A3. The intermediate shaft 188 is coaxial with the intermediate shaft axis A4. In some embodiments, the intermediate shaft 188 extends through the driven gear 160 to be received into the crankshaft 164 to directly provide torque thereto. In other embodiments, the intermediate shaft 188 terminates at the driven gear 160, and the crankshaft 164 is directly connected (e.g., using fasteners, key / keyway arrangements, press fits, etc.) to the second side 180 of the driven gear 160.

[0053] With continued reference to Figure 2A The second side 180 of the driven gear 160 includes a track plate 194 having a cam surface 196 that extends around the intermediate shaft axis A4. In the illustrated embodiment, the track plate 194 is coupled to the driven gear 160 at an interface 197. In other words, the track plate 194 and the driven gear 160 are formed as separate components and connected together in an after-manufacturing process (e.g., welding, threaded connection, etc.). In other embodiments, the cam surface 196 is integrated with the driven gear 160. In other words, the track plate 194 and the driven gear 160 are formed as a single piece. The cam surface 196 defines a continuously sloped edge 198 around an outer periphery 200 of the driven gear 160 that slopes between a region of a highest height 204 to a region of a lowest height 208. The highest height 204 is a point on the cam surface 196 at a distance XI measured in a direction parallel to the intermediate shaft axis A4 relative to the motor axis A3. The distance XI is the maximum distance of a point on the cam surface 196 relative to the motor axis A3. The lowest height 208 is a point on the cam surface 196 at a distance X2 measured in a direction parallel to the intermediate shaft axis A4 relative to the motor axis A3. The distance X2 is the minimum distance of a point on the cam surface 196 relative to the motor axis A3. A follower 212 engages and travels along the cam surface 196 to provide pivotal or orbital motion to the spindle assembly 152A, as will be described in detail below.

[0054] The crankshaft 164 includes a central hub 216, a first eccentric portion 218 extending from a first side 228 of the hub 216, and a second eccentric portion 224 extending from an opposite second side 232 of the hub 216. As Figure 2AAs shown, the first eccentric portion 218 and the second eccentric portion 224, which accounts for most of the radial width, are always located on opposite sides of the intermediate shaft axis A4. An eccentric pin 220 extends from the first eccentric portion 218 and is received in the spindle assembly 152A to provide reciprocating motion, which will be described in further detail later. A drive bushing 240 extends around the eccentric pin 220 to allow the eccentric pin 220 to rotate during operation.

[0055] like Figure 2A As shown, spindle assembly 152A includes a spindle 256 and a spindle frame 260, the spindle frame 260 supporting the reciprocating motion of the spindle 256 along the spindle axis A1. The spindle 256 includes a channel 270 in which a drive bushing 240 is received in a loosely sliding fit. The channel 270 has a length dimension perpendicular to the length orientation of the spindle 256. Therefore, the combination of the spindle 256 including the channel 270 and the first eccentric portion of the crankshaft 164 defines a stop yoke mechanism for converting the rotational motion of the crankshaft 164 into the linear reciprocating motion of the spindle 256. A saw blade clamp 271 is attached to the front end 268 of the spindle 256, ensuring that the saw blade 104 reciprocates in unison with the spindle 256. The saw blade clamp 271 includes a saw blade connection hole 272 coupling the saw blade 104 to the saw blade clamp 271. The saw blade connection hole 272 defines a saw blade connection axis A5. The saw blade connecting axis A5 is parallel to the pivot axis A2. The opposite rear end 273 of the spindle 256 extends through the rear of the spindle frame 260, ensuring that both ends 268, 273 of the spindle 256 are continuously supported by the spindle frame 260 throughout the entire range of motion of the spindle 256. The spindle assembly 152A includes a first bushing 276A and a second bushing 278. Figure 2A In the illustrated embodiment, the spindle 256 is supported in reciprocating motion by a first bushing 276A received by the spindle frame 260 and a second bushing 278 received by the spindle frame 260. In the illustrated embodiment, the spindle frame 260 is configured as a single component (i.e., a monolithic construction) to receive the first bushing 276A and the second bushing 278. In other constructions, the spindle frame 260 is composed of multiple components. For example, the spindle frame 260 includes a forward bushing carrier supporting the second bushing 278 and a backward bushing carrier supporting the first bushing 276A. That is, the forward bushing carrier and the backward bushing carrier are separate from each other. In some constructions, the second bushing 278 is pivotally coupled to a pivot shaft 288 and pivotally supports the spindle 254, which allows the forward bushing carrier to be fixed (e.g., not pivoted).

[0056] like Figure 2AAs shown, the saw 100 also includes a counterweight 280A that reciprocates out of phase with the main shaft 256 about rotation of the second eccentric 224 about the axis of rotation A4. The counterweight 280A is an elongated plate 282 that is parallel to the motor axis A3. The counterweight 280A includes a slot sandwiched between the central hub 216 and the driven gear 160 to receive the second eccentric 224. The counterweight 280A reciprocates between a forward position and a rearward position in response to rotation of the crankshaft 164 through the driven gear 160. In the illustrated configuration, the counterweight 280A reciprocates in a direction parallel to the axis A1. In other words, the counterweight 280A is a translational counterweight. The counterweight 280A provides vibration damping to the reciprocating saw 100 by counteracting the unbalanced forces caused by the main shaft assembly 152A.

[0057] Referring to Figure 2Apivot joint 284. The pivot joint 284 includes a pivot shaft 288 extending through the spindle frame 260 and defining a pivot axis A2. The spindle frame 260 is free to rotate about the pivot shaft 288 in response to interaction of the follower 212 with the cam surface 196 of the driven gear 160. The follower 212 is coupled to the spindle assembly 152A. In the illustrated embodiment, the follower 212 is fixed to a rear portion 290 of the spindle frame 260. In some embodiments, the follower 212 is a roller member that receives the rear portion 290 of the spindle frame 260. In other embodiments, the follower 212 is the rear portion 290 of the spindle frame 260. As the driven gear 160 rotates in the first direction Dl about the shaft axis A4, the follower 212 engages the cam surface 196 about the outer periphery 200 of the second side 180 of the driven gear 160. When the driven gear is viewed from the shaft axis A4 with the spindle frame 260 proximate the viewer, the first direction Dl is considered a counterclockwise direction. As the follower 212 engages the cam surface 196 from the highest height 204 to the lowest height 208, the rear portion 290 of the spindle frame 260 pivots downward (e.g., about the pivot shaft 288), causing the front portion 292 of the spindle frame 260 to pivot upward, as the front portion 292 is disposed on the opposite side of the pivot axis A2. In other words, as the follower 212 engages the cam surface 196 from the highest height 204 to the lowest height 208, the saw blade connection axis A5 rises, and the saw blade 104 rises accordingly. As the follower 212 engages from the lowest height 208 to the highest height 204, the rear portion 290 of the spindle frame 260 pivots upward (e.g., about the pivot shaft 288), causing the front portion 292 to pivot downward. Continued movement of the follower 212 between the highest height 204 and the lowest height 208 causes orbital movement of the spindle 256 about the pivot shaft 288. A biasing member 294 (e.g., a spring) is coupled to and positioned between the spindle frame 260 and the housing 108 to provide a restoring moment to the spindle frame 260 about the pivot axis A2 in the counterclockwise direction.

[0058] In operation, a user depresses the trigger 130 on the handle 128 to activate the motor 112. The motor 112 provides torque to the motor output shaft 148, causing it to rotate about the motor axis A3. The drive pinion 156 receives torque from the motor output shaft 148, causing it to rotate and drive the driven gear 160 and the intermediate shaft 188 to rotate about the intermediate shaft axis A4. Torque from the driven gear 160 (or, alternatively, the intermediate shaft 188) is transmitted to the crankshaft 164, causing the crankshaft 164 to rotate about the intermediate shaft axis A4. With the first eccentric portion 218 offset from the intermediate shaft axis A4, the main shaft 256 reciprocates through the eccentric pin 220 and the drive bushing 240, which are slidably housed in the channel 270. Specifically, the main shaft 256 reciprocates relative to the main shaft frame 260 between a back dead center (BDC) position and a front dead center (FDC) position. In the BDC position, the channel 270 is disposed closer to the motor 112 along the main shaft axis Al relative to the FDC position. In the FDC position, the channel 270 is disposed closer to the pivot joint 284 along the main shaft axis Al relative to the BDC position. A forward stroke occurs when the main shaft 256 travels from the BDC position to the FDC position. A reverse stroke occurs when the main shaft 256 travels from the FDC position to the BDC position. In the illustrated implementation, the saw blade 104 is configured to cut the workpiece 134 during the reverse stroke. In other implementations, the saw blade 104 is configured to cut the workpiece 134 during the forward stroke. The counterweight 280A reciprocates through the second eccentric portion 224 that is 180 degrees out of phase with the main shaft 256, thereby damping the vibrations from the reciprocating main shaft 256 and the saw blade 104. Further, as the driven gear 160 rotates, the follower 212 engages the cam surface 196 to continuously pivot the main shaft frame 260 about the pivot shaft 288. The simultaneous reciprocation of the main shaft 256 through the first eccentric portion 218 and the reciprocating pivotal motion of the main shaft frame 260 through the engagement of the follower 212 on the cam surface 196 and the restorative force provided by the spring 294 results in the main shaft 256 and the attached saw blade 104 moving in an orbital path. By orbitally moving the saw blade 104 in this manner, the cutting operation of the workpiece 134 can be performed more efficiently as compared to translating the saw blade 104 in a mere reciprocating manner.

[0059] Figure 2BAnother embodiment of a drive mechanism 110B and spindle assembly 152B compatible with the reciprocating saw 100 is shown. The drive mechanism 110B and spindle assembly 152B are similar to the drive mechanism 110A and spindle assembly 152A, respectively, so only the differences will be discussed. In the illustrated configuration, the spindle assembly 152B includes a bushing 276B having a cylindrical portion 295 that receives the follower 212. In other configurations, the follower 212 is received on the spindle frame 260. With respect to the drive mechanism 110B, the first eccentric portion 218 is received on the orbiting plate 194 (i.e., the drive mechanism 110B does not include the central hub 216 and the second eccentric portion 224). In the illustrated configuration, the counterweight 280B includes a gear 296 (e.g., a counterweight gear) that provides vibration dampening to the reciprocating saw 100 by counteracting the unbalanced forces induced by the spindle assembly 152B. The counterweight gear 296 rotates about an axis A4. In the illustrated embodiment, the plane Y1 includes the axis A3 and is perpendicular to the axis A4. The gear 296 is configured on an opposite side of the plane Y1 from the driven gear 160. In other words, the gear 296 is configured on an opposite side of the plane Y1 from the driven gear 160.

[0060] Figure 2C Another embodiment of a drive mechanism 110C and spindle assembly 152C compatible with the reciprocating saw 100 is shown. The drive mechanism 110C and spindle assembly 152C are similar to the drive mechanism 110A and spindle assembly 152A, respectively, so only the differences will be discussed. The driven gear 160 is spaced apart from the orbiting plate 194. In particular, the driven gear 160 is disposed on an opposite side of the plane Y1. The orbiting plate 194 is coupled to co-rotate with the intermediate shaft 188. The spindle assembly 152C includes a first bushing 276C. The first bushing 276C includes a spindle portion that surrounds the spindle 256 and an auxiliary portion 297 that extends from the spindle portion toward the orbiting plate 194. In particular, the auxiliary portion 297 extends parallel to the axis of rotation A4. The auxiliary portion 297 includes a hole 298 that extends through the auxiliary portion in a direction parallel to the motor axis A3. The hole 298 receives a post 299 that receives the follower 212.

[0061] Figure 3 and Figure 4 Another embodiment of a drive mechanism 110C and spindle assembly 152C compatible with the reciprocating saw 100 is shown. The drive mechanism 110C and spindle assembly 152C are similar to the drive mechanism 110A and spindle assembly 152A, respectively, so only the differences will be discussed. The driven gear 160 is spaced apart from the orbiting plate 194. In particular, the driven gear 160 is disposed on an opposite side of the plane Y1. The orbiting plate 194 is coupled to co-rotate with the intermediate shaft 188. The spindle assembly 152C includes a first bushing 276C. The first bushing 276C includes a spindle portion that surrounds the spindle 256 and an auxiliary portion 297 that extends from the spindle portion toward the orbiting plate 194. In particular, the auxiliary portion 297 extends parallel to the axis of rotation A4. The auxiliary portion 297 includes a hole 298 that extends through the auxiliary portion in a direction parallel to the motor axis A3. The hole 298 receives a post 299 that receives the follower 212. Figure 2A and 2BThe track plate 194 shown in FIG. 1 is compatible with a track plate 300 (e.g., a transmission member) of the drive mechanisms 110A and 110B. Specifically, the track plate 300 and the driven gear 160 are connected together in a post-manufacturing process (e.g., welding, threading, etc.). In some embodiments, the saw 100 is a direct drive saw (e.g., without a gear reduction). For example, the motor output shaft 148 is directly coupled to the track plate 300 such that the motor axis A3 is perpendicular to the spindle axis Al. The track plate 300 includes a body 304 that is structurally monolithic and includes a central hole 308 that is concentric with the intermediate shaft axis A4. In the illustrated embodiment, the central hole 308 extends through the entire body 304. As shown in FIG. 1, the central hole 308 is a counterbore hole. In the illustrated embodiment, the counterbore is disposed on a first side 312 of the body 304 opposite the second side 316. In some embodiments, the central hole 308 is configured to receive a fastener (not shown) to couple the track plate 300 to the driven gear 160 at the interface 197. Figure 4 Figure 2A and 2B In other embodiments, the track plate 300 is integrated with the driven gear 160. That is, the features described in connection with the track plate 300 are integrated into the second side 180 of the driven gear 160.

[0062] Referring to Figure 3 and Figure 4 The track plate 300 includes a hole 320 disposed radially outward relative to the intermediate shaft axis A4. In the illustrated embodiment, the hole 320 includes a counterbore disposed on the second side 316 of the body 304. The hole 320 is configured to receive an eccentric drive member (e.g., a fastener, a pin, etc.) that couples the track plate 300 to the spindle 256. In some embodiments, a fastener (not shown) couples the track plate 300 to the center hub 216 to provide the arrangement shown in FIGS. 1 and 2. Figure 2A and 2B For simplicity, Figure 3 The schematic illustration of the eccentric pin 220 being received by the hole 320 makes the position of the eccentric pin 220, and thus the position of the spindle 256 relative to the driven member 212, clear. However, Figure 3 The schematic illustration is not limiting of the track plate 300 coupling to the eccentric pin 220. Rather, the track plate 300 is indirectly attached to the eccentric pin 220. For example, the non-limiting embodiment of the track plate 300 shown in FIG. 3 is indirectly attached to the eccentric pin 220 via the center hub 216 as shown in FIG. 4. Figure 2A

[0063] ​​The track plate 300 includes a cam surface 324 disposed on an outermost periphery (e.g., edge) of the main body 304. The cam surface 324 is disposed on the first side 312 of the main body 304. The cam surface 324 has a variable profile that, when "unwrapped," is represented as a variable waveform that serves as a measure of the follower 212 displacement as a function of the track plate 300 phase angle. In the illustrated embodiment, the waveform is defined by a first equation (see, e.g., the first waveform 336 described below and illustrated in Figure 5 ) over a first phase angle range of the cam surface 324 and a second equation (see, e.g., the second waveform 340 described below and illustrated in Figure 5 ) over a second phase angle range of the cam surface 324. In other words, the waveform is a piecewise function. More specifically, the waveform is a piecewise function using two sinusoidal waves. In other embodiments, the waveform is a single polynomial equation (e.g., B-spline function, Taylor series approximation, etc.). Specifically, the waveform is a mathematical function that approximates Figure 5 the respective piecewise functions illustrated. In each case, the waveform 336, 340 can be defined with one equation (e.g., a high order polynomial function) or multiple equations (e.g., a piecewise function) that are associated with the follower 212 displacement as a function of the track plate 300 phase angle.

[0064] Referring to Figure 3 and Figure 4 , the follower 212 is schematically illustrated configured to engage the cam surface 324. As described above, during rotation of the track plate 300, the follower 212 pivots about the pivot axis A2 Figure 2A and 2B . The cam surface 324 includes a first segment 328 and a second segment 332. The first segment 328 defines the first waveform 336 and the second segment 332 defines the second waveform 340 Figure 5 . As discussed above in connection with the cam surface 196, the cam surface 324 is continuously sloped from a highest height point to a lowest height point. The waveforms 336, 340 of the first segment 328 and the second segment 332 collectively define a continuous slope. That is, the continuous slope is created by the piecewise function of two sinusoidal waves. In the illustrated embodiment, the first waveform 336 is different than the second waveform 340. In other words, the shape of the first segment 328 is different than the shape of the second segment 332. The first segment 328 and the second segment 332 intersect at a first point PI and a second point P2.

[0065] Referring to Figure 3 and Figure 4 , the track plate 300 is rotated counterclockwise from the frame of reference of Figure 3 about the intermediate axis A4. It will be described as if the track plate 300 is rotated clockwise from the frame of reference of Figure 3the first and second segments 328, 332 when the eccentric pin 220 is disposed in the FDC position. In other words, the angular reference of the track plate 300 when the eccentric pin 220 is in the FDC position (i.e., the eccentric pin 220 is in the position closest to the pivot joint 284 along the main shaft axis Al) will be described. In the FDC position, the eccentric pin 220 is at 180 degrees and the follower 212 is at 0 degrees. The first segment 328 extends around the cam surface 324 with a first angular span SI. In some embodiments, the angular span SI is less than 180 degrees. In some embodiments, the angular span SI is between 50 degrees and 170 degrees. More specifically, in the illustrated embodiment, the first angular span SI is approximately 90 degrees. The second segment 332 extends around the cam surface 324 with a second angular span S2. In the illustrated embodiment, the second angular span S2 is approximately 270 degrees. The angular span S2 extends the remaining portion of the cam surface 324 relative to the intermediate shaft axis A4. The sum of the first angular span SI and the second angular span S2 is 360 degrees (e.g., the entire circumference of the cam surface 324). Figure 3 The angular span SI as measured in a clockwise direction from the reference frame of the eccentric pin 220 extends from 150 degrees to 240 degrees relative to the intermediate shaft axis A4. The second segment 332 extends around the cam surface 324 with a second angular span S2. In the illustrated embodiment, the second angular span S2 is approximately 270 degrees. The angular span S2 extends the remaining portion of the cam surface 324 relative to the intermediate shaft axis A4. The sum of the first angular span SI and the second angular span S2 is 360 degrees (e.g., the entire circumference of the cam surface 324).

[0066] Referring to Figure 3 and Figure 4 , the first point PI is angularly offset from the eccentric pin 220 by an included angle a relative to the intermediate shaft axis A4. In some embodiments, the included angle is between -180 degrees and 180 degrees. In some embodiments, the included angle a is between -15 degrees and 90 degrees. In the illustrated embodiment, the included angle a is 30 degrees.

[0067] Figure 5 The cam surface 324 is shown with its continuously sloped edge "unwrapped" as a wave shape. Specifically, the wave shape is a sinusoidal piecewise function 348. The function 348 includes the combined wave shapes 336, 340. The X-axis represents the angular position of the cam surface 324 from 0 degrees to 360 degrees (e.g., as shown in Figure 3 The Y-axis represents the displacement of the surface 352 of the follower 212 as it engages the cam surface 324 in a direction parallel to the intermediate shaft axis A4 (e.g., the z-direction) when the eccentric pin 220 is disposed in the FDC position. Figure 2A and 2B In other words, the Y-axis represents the height or amplitude variation of the cam surface 324 relative to a direction parallel to the intermediate shaft axis A4 (e.g., the z-direction).

[0068] As Figure 5As shown, the first waveform 336 and the second waveform 340 share a common amplitude. That is, the waveforms 336, 340 share a peak-to-peak value, which makes them identical and continuous at points PI, P2. The first waveform 336 has a higher frequency than the second waveform 340 (if repeated for the entire 360-degree arc length of the cam surface 324) if repeated for the entire 360-degree arc length of the cam surface 324. For example, the first waveform 336 extends from peak to peak with an angular span of 90 degrees, and the second waveform 340 extends from peak to peak with a span of 270 degrees Figure 3 and 5 ). Thus, the height change in the first section 328 is faster than the height change in the second section 332.

[0069] As shown, Figure 5 the sections 328, 332 define an average slope with dashed lines. The average slope (e.g., M) corresponds to The first section 328 defines a first average slope Ml. The first point PI is set at 150 degrees and about 1.8 mm (e.g., xl= 150, yl= 1.8 mm). The second point P2 is set at 240 degrees and about -1.8 mm (e.g., x2= 240, y2= -1.8 mm). Thus, the first average slope Ml of the first section 328 is about -0.04 mm / degree (e.g., ). The second section 332 defines a second average slope M2. The first point PI and the second point P2 are located at the same position, but the second average slope M2 spans from 0 degrees to 150 degrees and from 240 degrees to 360 degrees (i.e., a total of 270 degrees). Thus, the second average slope M2 of the second section 332 is about 0.013 mm / degree (e.g., ). The magnitude of the first average slope Ml is greater than the magnitude of the second average slope M2. Specifically, the magnitude of the first average slope Ml is between 1.5 times and 4 times the magnitude of the second average slope M2. Specifically, in the illustrated configuration, the magnitude of the first average slope Ml (e.g., 0.04 mm / degree) is 3 times the magnitude of the second average slope M2 (e.g., 0.013 mm / degree). In the illustrated configuration, the first average slope Ml and the second average slope M2 are taken between peak-to-peak values (e.g., the first point PI and the second point P2). In comparison to the prior art, the cam surface 324 has two sections 328, 332 that define slopes that are different from each other. With the prior art track plate, there is only a single section that defines a single slope (e.g., a single waveform with a constant frequency).

[0070] Figures 6-8 The track plate 300 is shown at different phase angles relative to the follower 212 as the track plate 300 rotates about the intermediate shaft axis A4. Figure 6The track plate 300 is shown at the first rotational position R1, where the follower 212 engages the first point P1. Figure 7 The track slab at the BDC location is shown. Figure 8 The track plate 300 is shown at the second rotational position R2, where the follower 212 engages the second point P2. As the follower 212 engages the cam surface 324, the main shaft 256 pivots about the pivot axis A2. Figure 2A and 2B ).

[0071] Figure 9 The displacement of the saw blade connecting axis A5 (including both the forward and reverse strokes of the spindle 256) for a full 360-degree rotation of the track plate 300 about the intermediate axis A4 is shown. Specifically, at the FDC position ( Figure 3 The displacement of the saw blade connecting axis A5 relative to the pivot axis A2 in a direction parallel to the intermediate axis A4 is zero. In other words, the position of the saw blade connecting axis A5 at the FDC position of the spindle 256 is a reference or datum position relative to the forward and reverse strokes (i.e., the displacement of the saw blade connecting axis A5 at the FDC position is zero). Figure 9 As shown, a reverse travel occurs from the FDC position (i.e., 0 degrees) to the BDC position (i.e., 180 degrees). Figure 9 As shown, a forward stroke occurs from the BDC position (i.e., 180 degrees) to the FDC position (i.e., 360 degrees).

[0072] See Figure 5 As track plate 300 moves from FDC position ( Figure 3 Rotate to BDC position ( Figure 7 During the reverse stroke, the saw blade connecting axis A5 is displaced by a reverse displacement T1 (e.g., the maximum reverse displacement). Specifically, the reverse displacement T1 is the displacement relative to the saw blade connecting axis A5 at the FDC position during the reverse stroke. Figure 3 The maximum horizontal displacement at point 324. In other words, the reverse displacement T1 is the maximum y-axis value reached by the saw blade connecting shaft A5 during the reverse stroke. In some configurations, the reverse displacement T1 occurs between phase angles of 110 and 190 degrees. In the configuration shown, the reverse displacement T1 occurs at a phase angle of 150 degrees. In some embodiments, the reverse displacement T1 of the saw blade connecting shaft A5 is between 0.02 inches (e.g., 0.51 mm) and 0.06 inches (e.g., 1.5 mm). In the embodiment shown, the reverse displacement T1 of the saw blade connecting shaft A5 is approximately 0.04 inches (e.g., 1 mm). In the embodiment shown, when the follower 212 engages the cam surface 324 ( Figure 6 At the first point P1 on the cam, the saw blade connecting axis A5 shifts in the opposite direction by a displacement T1. In other words, the first point P1 defines the cam surface 324 (Figure 5 ) coincides with a high point on the cam surface 324( Figure 9 ) relative to the pivot axis A2 in a direction parallel to the intermediate shaft axis A4.

[0073] Referring to Figure 5 , as the track plate 300 rotates from the BDC position( Figure 7 ) to the FDC position( Figure 3 ), the saw blade connection axis A5 is displaced by a forward displacement T2 (e.g., a forward maximum displacement) during the forward stroke. In particular, the forward displacement T2 is the maximum displacement of the saw blade connection axis A5 during the forward stroke relative to the horizontal position of the saw blade connection axis at the FDC position( Figure 3 ). In other words, the forward displacement is the maximum value of the y-axis reached by the saw blade connection axis A5 during the forward stroke. In some constructions, the forward displacement T2 occurs when the phase angle is between 200 degrees and 280 degrees. In the illustrated construction, the forward displacement T2 occurs at a phase angle of 240 degrees. In some constructions, the forward displacement T2 of the saw blade connection axis A5 is between 0.01 inch (e.g., 0.25 millimeter) and 0.05 inch (e.g., 1.27 millimeter). In the illustrated embodiment, the displacement T2 of the saw blade connection axis A5 is about 0.03 inch (e.g., 0.75 millimeter). In the illustrated embodiment, the saw blade connection axis A5 is displaced by the forward displacement T2 when the follower 212 engages a second point P2 on the cam surface 324( Figure 8 ). In other words, the second point P2 defines a low point on the cam surface 324( Figure 5 ) that coincides with a high point of the saw blade connection axis A5( Figure 9 ) relative to the pivot axis A2 in a direction parallel to the intermediate shaft axis A4. The total displacement T3 of the saw blade connection axis A5 is the sum of the reverse displacement T1 and the forward displacement T2. In some constructions, the total displacement is between 0.03 inch (e.g., 0.7 millimeter) and 0.11 inch (e.g., 2.8 millimeter). In the illustrated construction, the total displacement T3 is about 0.07 inch (e.g., 1.75 millimeter).

[0074] Figure 9 The saw blade connection axis A5 is shown displaced by the total displacement T3 from the first rotational position R1( Figure 6 ) to the second rotational position R2( Figure 8 ). Conversely, the saw blade connection axis A5 is displaced by the total displacement T3 from the second rotational position R2( Figure 8 ) to the first rotational position R1( Figure 6The total displacement T3 is shifted during this process. In other words, the saw blade connecting axis A5 experiences the same displacement in the first segment 328 and the second segment 332. However, the first segment 328 occupies 90 degrees of the total arc length of the cam surface 324, while the second segment 332 occupies 270 degrees of the total arc length of the cam surface 324 (e.g., the first segment 328 is one-third of the angular span S2 of the second segment 332). Due to the first waveform 340 ( Figure 5 At higher frequencies, the first segment 328 achieves the same displacement as the second segment 332 within a smaller angular span. In some embodiments, the displacement experienced by the saw blade connecting axis A5 in the first segment 328 is not the total displacement T3. In other words, the displacement experienced by the saw blade connecting axis A5 in the first segment 328 is different from the displacement experienced in the second segment 332. In such embodiments, the first segment 328 causes the saw blade connecting axis A5 to be displaced between 80% and 100% of the total displacement T3.

[0075] The displacements T1 and T2 of the saw blade connecting axis A5 depend on the dimensions of saw 100. For example, as Figure 2A and Figure 2B As shown, the distance X3 measured from follower 212 to intermediate shaft axis A4, the distance X4 measured between pivot axis A2 and intermediate shaft axis A4, the distance X5 measured between main shaft axis A1 and pivot axis, the distance X6 measured between eccentric pin 220 and intermediate shaft axis A4, and the distance X7 measured between saw blade connecting axis A5 and eccentric pin 220 each affect the displacement of saw blade connecting axis A5 relative to pivot axis A2. In the illustrated embodiment, distance X3 is approximately 1.3 inches (e.g., 33 mm), distance X4 is approximately 2.5 inches (e.g., 65 mm), distance X5 is approximately 0.7 inches (e.g., 17 mm), distance X6 is approximately 0.625 inches (e.g., 15.88 mm), and distance X7 is approximately 5 inches (e.g., 128.91 mm). In some configurations, distance X6 is between 0.625 inches and 0.75 inches. Therefore, the total displacement T3 of the saw blade connecting axis A5 is only due to the follower 212 due to the cam surface 324 ( Figure 5 The displacements resulting from this are represented by the slopes (e.g., the first average slope M1 and the second average slope M2), which depend on the dimensions of the saw 100, in addition to the displacements T1 and T2.

[0076] Figure 9It is shown that from the FDC position, during the reverse stroke, the saw blade connection axis A5 is gradually lowered from the FDC position to the first rotational position R1 position, thereby gradually engaging the teeth of the saw blade with the workpiece 134. From the first rotational position R1 to the second rotational position R2, the saw blade connection axis A5 is rapidly raised due to the first section 328 (e.g., the first point P1) engaging the first wave form 340. The first section 328 is disposed on the cam surface 324, which makes the rapid rise not occupy a large portion of the reverse stroke. In other words, a large portion of the reverse stroke is reserved for the lowering of the saw blade connection axis A5. Additionally, the rapid rise results in the saw blade 104 being gradually lifted out of the workpiece 134 proximal to the BDC position, which makes the saw blade 104 not catch the workpiece 134 on the forward stroke, thereby preventing kickback. For example, if the saw blade 104 does not pull out of the workpiece 134 before the BDC position, the forward stroke begins and causes the tool to kickback to the user. From the second rotational position R2 to the FDC position, the saw blade connection axis A5 is gradually lowered, consistent with the lowering of the saw blade towards the workpiece 134. The saw blade 104 is lowered from the second rotational position R2 to the first rotational position R1.

[0077] Figure 9 It is also shown that there is a first maximum velocity V1 and a second maximum velocity V2. The first maximum velocity V1 occurs during the reverse stroke and the second maximum velocity V2 occurs during the forward stroke. Both velocities V1, V2 are disposed at the midpoint between the FDC position and the BDC position (i.e., the first maximum velocity V1 is at 90 degrees on the cam surface and the second maximum velocity is at 270 degrees on the cam surface).

[0078] Figure 10Displacements of the saw blade connection axis A5 in relation to the track plate 300, the first prior art track plate 356, and the second prior art track plate 360 are shown. The track plate 356 includes a cam surface (not shown) having a single wave form (and thus defining a single frequency) across a 360 degree arc length of the cam surface. The displacement of the saw blade connection axis A5 for the track plate 356 is determined using the saw 100, which has the same distances X3-X7 as recorded for the track plate 300. The track plate 360 includes a cam surface (not shown) having a single wave form (and thus defining a single frequency) across a 360 degree arc length of the cam surface. In the illustrated embodiment, the frequency of the cam surface of the track plate 360 is approximately the same as the frequency of the cam surface of the track plate 356. However, the displacement of the saw blade connection axis A5 for the track plate 360 is determined using the saw 100, which has different distances X3-X7. Specifically, the saw 100 used with the track plate 360 has a distance X3 of approximately 1.3 inches (e.g., 32.75 millimeters), a distance X4 of approximately 2.6 inches (e.g., 67.5 millimeters), a distance X5 of approximately 0.50 inches (e.g., 13.5 millimeters), a distance X6 of approximately 0.63 inches (e.g., 15.88 millimeters), and a distance X7 of approximately 5 inches (e.g., 126.7 millimeters). The track plate 360 shows the effect of the distances X3-X7 on the displacement of the track plate 360. The rise of the saw blade connection axis A5 for the track plates 356, 360 takes approximately 180 degrees, while the track plate 300 takes 90 degrees (i.e., the first section 328).

[0079] The timing of the raising and lowering of the saw blade connection axis A5 (and thus the changing of the inclination of the saw blade 104 relative to the workpiece 134 to be cut) affects the efficiency of the cut (e.g., the time to complete the cut). The saw blade 104 is configured to cut the workpiece 134 during the reverse stroke. For example, the saw blade 104 includes teeth having a serrated edge that are shaped to cut the workpiece 134 during the reverse stroke. Lowering the saw blade 104 during the reverse stroke increases the efficiency of the cut because the saw blade 104 is displaced toward the workpiece 134. As noted above in connection with the track plate 300, the saw blade 104 is configured to cut the workpiece 134 during the reverse stroke. For example, the saw blade 104 includes teeth having a serrated edge that are shaped to cut the workpiece 134 during the reverse stroke. Lowering the saw blade 104 during the reverse stroke increases the efficiency of the cut because the saw blade 104 is displaced toward the workpiece 134. Figure 9As discussed, when using track plate 300, the saw blade connection axis A5 is gradually lowered from the FDC position to the first rotational position R1 position during the reverse stroke. In contrast, when using track plate 356, the saw blade connection axis A5 begins to rise during the reverse stroke approximately when the spindle end displacement is 0.6 inches in the x-direction (e.g., midway between the FDC position and the BDC position). When using track plate 360, the saw blade connection axis A5 begins to rise approximately midway when the spindle end displacement is 0.5 inches in the x-direction during the reverse stroke. In other words, the saw blade connection axis A5 rises earlier during the reverse stroke when using plates 356, 360 as compared to plate 300. Because the rise of the saw blade connection axis A5 begins earlier for plates 356, 360, there is less displacement toward the workpiece 134 during the reverse stroke, cutting efficiency is reduced (e.g., increasing cutting time).

[0080] The timing of the raising and lowering of the saw blade connection axis A5 (and thus the changing of the inclination of the saw blade 104 relative to the workpiece 134 being cut) also affects the vibration experienced by the user. As discussed above, the saw blade used for the reciprocating saw 100 is configured to cut on the reverse stroke, and not cut into the workpiece 134 during the forward stroke. During the forward stroke, because the saw 100 is pushed away from the workpiece 134 for lack of cutting, the contact of the saw blade 104 with the workpiece 134 causes vibration of the saw 100. The contact of the saw blade 104 with the workpiece 134 can occur near the BDC position because the saw blade 104 is not pulled out of the workpiece 134 quickly enough. As discussed above in connection with FIG. 3, the saw blade 104 is pulled out of the workpiece 134 more quickly when using plate 300 as compared to plates 356, 360. Thus, the vibration of the saw 100 is less when using plate 300 as compared to plates 356, 360. Figure 9 As discussed, because of the high frequency of the first segment 328, which occupies 90 degrees of the total arc length of the cam surface 324, the saw blade 104 is actively lifted out of the workpiece 134 proximate the BDC position. The fast rise of the first segment 328 ensures that the saw blade 104 is out of the workpiece 134. In contrast, when using track plates 356, 360, the saw blade connection axis A5 is lifted out of the workpiece 134 at a slower rate. This is because the track plates 356, 360 have a lower frequency in lifting the saw blade 104 than plate 300. Thus, the saw blade 104 is less likely to contact the workpiece 134 near the BDC position when using plate 300 as compared to using plates 356, 360 because the saw blade 104 is more actively lifted out of the workpiece 134 than when using plates 356, 360. Thus, the saw 100 vibrates less when using plate 300 as compared to plates 356, 360.

[0081] In addition to preventing contact near the BDC position, lifting the saw blade 104 affects the timing of when the saw blade 104 next contacts the workpiece 134. Figures 11A-11C A plate 300 used in a saw 100 is shown. Figure 11A A saw blade 104 cutting a workpiece 134 is shown. The saw blade 104 defines a tooth plane Y2 that cuts the workpiece 134 at a cut plane Y3. In particular,Figure 11A The saw 100 is shown between the FDC and the first rotational position Rl during the reverse stroke. In other words, the blade 104 is cutting Figure 11A the workpiece 134. The tooth plane Y2 is in contact with the cut plane Y3 because the blade 104 is pushed toward the cut plane Y3 by the external force Fl. In some configurations, the external force is a combination of the user pressing the saw 100 against the workpiece and gravity.

[0082] Figure 11B The blade 104 is shown between the BDC position and the FDC position. As Figure 11B shown, the tooth plane Y2 is spaced apart from the cut plane Y3 by a distance X8. During the cutting motion (between the FDC position and the first rotational position Rl), the housing 108 moves upward due to the tilt of the blade 104 relative to the housing 108 and the downward motion of the blade 104, thus separation occurs between the tooth plane Y2 and the cut plane Y3. Additionally, the blade connection axis A5 and the rapid ascent of the blade 104 due to the first section 328 contribute to the separation. During the forward stroke, the distance X8 between the planes Y2, Y3 decreases as the external force Fl directs the saw 100 toward the workpiece 134. The separation between the planes Y2, Y3 prevents the blade 104 from contacting the workpiece 134 during the forward stroke, thus reducing vibration.

[0083] Figure 11C The blade 104 is shown in the FDC position. The tooth plane Y2 is configured to first contact the cut plane Y3 at the FDC position, which causes the blade 104 to begin cutting the workpiece 134 from the beginning of the reverse stroke, thus maximizing the contact time between the tooth plane Y2 and the cut plane Y3. In other words, having the tooth plane Y2 land on the cut plane Y3 at the FDC position increases cutting efficiency because of the maximum contact time between the tooth plane Y2 and the cut plane Y3. In the event that the separation distance X8 is too great, the tooth plane Y2 will first contact the cut plane Y3 during the reverse stroke between the FDC position and the BDC position, resulting in less contact time between the tooth plane Y2 and the cut plane Y3 (i.e., decreased cutting efficiency). The concept of the tooth plane Y2 contacting the cut plane Y3 during the reverse stroke between the FDC position and the BDC position will be referred to as “overshoot” of the cut plane Y3. In the event that the separation distance X8 is too small, the tooth plane Y2 will first contact the cut plane Y3 during the forward stroke before the FDC position, thus increasing vibration due to the blade 104 contacting the workpiece 134 during the forward stroke. The concept of the tooth plane Y2 contacting the cut plane Y3 during the forward stroke before the main shaft 256 reaches the FDC position will be referred to as “undershoot” of the cut plane Y3.

[0084] Accordingly, the separation distance X8 between the planes of management Y2, Y3 affects the vibration and cutting efficiency of the tool. With the use of the plates 356, 360 in the saw 100, the distance X8 will be less than the distance X8 when using the plate 300 because the plates 356, 360 do not have the abrupt rise of the saw blade Figure 10 ) caused by the plates 356, 360, the saw 100 is prone to increased vibration from the saw blade contacting the workpiece 134 (e.g., undershoot the cutting plane Y3) before the FDC position.

[0085] Figure 12 The vibration experienced by the saw 100 with the plates 300, 356 is shown. In particular, Figure 12 The vibration shown is hand and arm vibration (HAV). As Figure 12 shown, the vibration is measured using acceleration (e.g., ). Bar 400 shows the saw 100 with the plates 356, and the acceleration is about Bar 404 shows the saw 100 with the plates 300, and the acceleration is about As described above, the reduced vibration of the saw 100 with the plates 300 can be attributed to the high frequency section. Without the high frequency section, the saw blade 104 can get stuck on the workpiece 134 near the BDC position when lifting from the workpiece 134, or contact the workpiece 134 before the FDC position due to insufficient separation between the planes Y2, Y3.

[0086] Figure 13 The average cutting duration (in seconds) of the saw 100 with variations of the orbital plate 300 having different included angles a is shown. As Figure 13 shown, the range of angles for the included angles a was recorded between -15 degrees and 120 degrees (e.g., -15 degrees, 30 degrees, 45 degrees, 60 degrees, 75 degrees, 90 degrees, 105 degrees, and 120 degrees). The plates 356 and 360 were included to provide a comparison to the prior art having a single frequency. The cutting duration was measured by recording the current of the saw 100 while cutting a workpiece (not shown) having a uniform thickness. For the test, a workpiece having a thickness of 1.75 inches and a depth of 16 inches was used. When the cutting was started, the current of the saw 100 jumped from the no-load condition (i.e., not contacting the workpiece) to the load condition (i.e., contacting the workpiece). The initial spike in current was recorded as the start time of the cut. When the saw 100 completed the cut, the motor 112 was unloaded and therefore no longer needed to draw a high current to continue rotating. The decrease in current was detected as the end time of the cut. Accordingly, the cutting duration was measured from the initial spike in current to the decrease in current.

[0087] As Figure 13As shown, the average cutting time for track plate 356 is 13.19 seconds. For track plate 360, the average cutting time is approximately 13.07 seconds. For plate 300, the average cutting time α is 12.14 seconds for a -15 degree angle, 11.43 seconds for a 30 degree angle, 11.80 seconds for a 45 degree angle, 14.58 seconds for a 60 degree angle, 14.98 seconds for a 75 degree angle, 14.98 seconds for a 90 degree angle, 16.48 seconds for a 105 degree angle, and 17.70 seconds for a 120 degree angle.

[0088] like Figure 13 As shown, the shortest cutting time for the workpiece occurs when the included angle α of the track plate 300 is within range B1. In some embodiments, range B1 extends from -15 degrees to 60 degrees. In the illustrated embodiment, range B1 extends from 20 degrees to 50 degrees. Specifically, in the illustrated embodiment, the shortest average cutting time occurs at an included angle α of 30 degrees. However, it is worth noting that range B1 can vary based on the saw distance X3-X7. For example, for distances other than the distances X3-X7 recorded by the track plate 300, range B1 includes angles α less than or greater than 30 degrees. That is, range B1 includes angles α between -180 degrees and 180 degrees.

[0089] In the illustrated embodiment, the average cutting time increases as the included angle α increases from 30 degrees (e.g., when the range B1 is between 30 degrees and 180 degrees). Figures 14-17 Each figure shows the displacement of the saw blade connecting axis A5 for a full 360-degree rotation of the track plate 300 around the intermediate axis A4 (including both the forward and reverse strokes of the spindle 256), wherein the included angle α of the track plate 300 is different. Figure 14 The track plate 300 with a 90-degree included angle α is shown. Figure 15 The track plate 300 with an included angle α of 75 degrees is shown. Figure 16 The track slab 300 with an included angle α of 60 degrees is shown. Figure 17 The track plate 300 with an included angle α of 45 degrees is shown.

[0090] and Figure 9 Compared to the included angle α (i.e., 30 degrees), Figures 14-17 The included angles α (i.e., 90 degrees, 75 degrees, 60 degrees, and 45 degrees) cause the saw blade connecting axis A5 to rise earlier during the reverse stroke, resulting in less cutting time and an increased average cutting duration. The saw blade connecting axis A5 begins to rise when engaging the first segment 328, which is shown between the first point P1 and the second point P2. That is, the saw blade connecting axis A5 begins to rise at the first point P1. Figures 14 to 17 As shown, the first point P1 is set at a ratio of Figure 9The angle position shown is further away from the BDC position, which means that the saw blade connecting axis A5 rises earlier in the reverse stroke. In addition, changing the included angle α to more than 30 degrees may cause the tooth plane Y2 to fall into the cutting plane Y3 because the saw blade 104 is lifted earlier, which leads to increased vibration.

[0091] In the illustrated embodiment, the average cutting time increases as the included angle α decreases from 30 degrees (e.g., when the range B1 is between -180 degrees and 30 degrees). Figures 18-20 Each figure shows the displacement of the saw blade connecting axis A5 for a full 360-degree rotation of the track plate 300 around the intermediate axis A4 (including both the forward and reverse strokes of the spindle 256), wherein the included angle α of the track plate 300 is different. Figure 18 The track slab 300 with an included angle α of 15 degrees is shown. Figure 19 The track slab 300 with a 0-degree included angle α is shown. Figure 20 The track plate 300 with an included angle α of -15 degrees is shown.

[0092] and Figure 9 Compared to the included angle α (i.e., 30 degrees), Figures 18-20 The included angle α (i.e., 15 degrees, 0 degrees, and -15 degrees) causes the saw blade connecting axis A5 to rise later, which results in the saw blade 104 leaving the workpiece 134 for a shorter time. Figures 11A-11C This causes the saw blade 104 to get stuck on the workpiece 134 during the forward stroke, resulting in increased vibration. Additionally, when the included angle α is between 0 degrees and -180 degrees, the saw blade connecting axis A5 moves downwards during a portion of the forward stroke, further increasing the vibration perceived by the user. For example, as... Figure 20 As shown, the saw blade connecting axis A5 continues to move downwards after the BDC position (i.e., 180 degrees) until it reaches P1 at 195 degrees (i.e., -15 degrees). Furthermore, changing the included angle α to less than 30 degrees may cause the tooth plane Y2 to overshoot the cutting plane Y3 because the saw blade 104 is lifted later. This results in less contact time between the tooth plane Y2 and the cutting plane Y3, and thus increases the average cutting time.

[0093] Figure 21 This shows the effect for a stroke length of 1.25 inches ( Figure 9), the saw blade connection axis A5 of the saw 100, the rail plate 300, and the full 360 degree rotation of the intermediate shaft axis A4. To change the stroke length, the distance X6 can be adjusted. For a stroke length of 1.25 inches, the distance X6 is 0.625 inches. For a stroke length of 1.375 inches, the distance X6 is 0.6875 inches. For a stroke length of 1.5 inches, the distance X6 is 0.75 inches. Increasing the stroke length and keeping the run speed will increase the performance of the tool. Specifically, the mechanical work done by the object (e.g., W(t)) is the product of the cutting force (e.g., F(t)) and the saw blade displacement (e.g., d) in the direction the saw blade teeth are oriented. The saw blade displacement d depends on the angle (e.g., Q) which depends on time (e.g., (t)). Thus, W(t) = F(t) · d(Q(t)). If the stroke length is increased, the saw blade displacement is more (i.e., the saw blade displacement d is increased), and thus the mechanical work is increased. The mechanical power (e.g., P(t)) is the rate at which the work is done, and can be represented as the time derivative of the mechanical work. Thus, When the mechanical work and mechanical power equations are combined, it reveals that the mechanical power (e.g., P(t)) is a function of the cutting force (e.g., F(t)) and the velocity (e.g., V x ) of the saw blade. Thus, P(t) = F(t) · V x .

[0094] Figure 22 The spindle axis velocity of the saw 100 using the rail plate 300 with a stroke length of 1.25 inches, a stroke length of 1.375 inches, and a stroke length of 1.5 inches is shown. For this study, the motor 112 was set to a constant speed for each different stroke length, which resulted in a constant reciprocating velocity (strokes per minute or SPM). In other words, the only variable that changed was the stroke length (e.g., distance X6). As shown in the graph of Figure 22 , the maximum velocity was approximately 6 m / s, and was performed by the saw 100 with a 1.5 inch stroke length. The next highest velocity value was approximately 5.5 m / s, and was performed by the 1.375 inch stroke length. The highest velocity value for the 1.25 inch stroke length was approximately 5 m / s.

[0095] Figure 23 Modeling demonstrates the average length of time for the saw 100 to cut, where the rail plate 300 has a variable stroke length. As shown in the graph of Figure 23As shown, the cut time of the saw 100 with the rail plate 300 decreases as the stroke length increases to about 1.5 inches. The decrease in cut time can be attributed to the increased stroke length increasing the blade speed and / or the increased cutting force due to the increased stroke length. However, as the stroke length is increased beyond 1.5 inches, the cut time begins to increase due to a decrease in tool control. Examples of tool control for the saw 100 include properly contacting the cut plane Y3 at the FDC location and maintaining a downward force Fl on the tool. An undercut or an overcut of the cut plane Y3 contributes to a decrease in tool control and, thus, an increase in cut time, as discussed previously in the application. For example, as the stroke length is moved beyond 1.5 inches, the saw 100 overcuts or undercuts the cut plane Y3, thereby increasing the cut time. In other words, the decrease in tool control outweighs the benefits of the increased stroke length (e.g., increased speed and decreased cutting force for cut time).

[0096] Figure 23 The saw 100 with the prior art rail plate having a variable stroke length (e.g., rail plates 356, 360) is also modeled in dashed lines. In comparison to the saw 100 with the rail plate 300 in solid lines, the cut time of the saw 100 with the prior art rail plate increases due to a decrease in tool control after the stroke length is increased beyond 1.375 inches.

[0097] The cut time of the saw 100 with the prior art rail plate (e.g., increased stroke length beyond 1.375 inches) increases earlier than the saw 100 with the rail plate 300 (e.g., increased stroke length beyond 1.5 inches) because the prior art rail plate does not manage the separation distance X8 between the planes Y2, Y3 when compared to the rail plate 300. Figures 11A-11C In other words, the prior art rail plate overcuts or undercuts the cut plane Y3, thereby decreasing tool control and increasing cut time. In addition to improving the cut performance of the saw 100 with the rail plate 300 by increasing the stroke length between 1.25 inches and 1.5 inches, the increased stroke length also improves the wear life of the blade 104.

[0098] Figure 24The saw blade 104 of the saw 100 that is in contact with the workpiece 134 is shown. The number of activated blade teeth (e.g., ABT) is equal to the product of the length of the saw blade 104 that will be subject to wear (e.g., WL) and the number of teeth per inch of saw blade cutting edge (e.g., TPI). Thus, ABT = WL - TPI. The length of the saw blade 104 that will be subject to wear (e.g., WL) is the sum of the tool stroke length (e.g., Stroke) and the beam thickness increase due to the saw blade angle (e.g., T'). Thus, WL = Stroke + T'. The number of teeth per inch of saw blade cutting edge (e.g., TPI) is equal to the dividend of the number of load sharing teeth (e.g., LS) and the beam thickness increase due to the saw blade angle (e.g., T'). Thus, The beam thickness increase due to the saw blade angle (e.g., T') is equal to the dividend of the beam thickness (e.g., X9) and the cosine of the saw blade angle (e.g., Θ). Thus,

[0099] The cumulative wear on the tooth edge of the saw blade 104 decreases as more teeth ABT are activated. The beam thickness X9 of the workpiece 134 is 1.5 inches. Figures 25A-25C The saw 100 in Table 1 has a stroke length of 1.25 inches, a saw blade angle Θ of 0 degrees, and a teeth per inch TPI of 5 (e.g., AX5 TPI blade). Thus, the activated teeth ABT is 13.75 teeth per tool stroke. For the saw 100 with a stroke length of 1.375 inches, a saw blade angle Θ of 0 degrees, and a teeth per inch TPI of 5 (e.g., AX5 TPI blade). Thus, the activated teeth ABT is 14.75 teeth per tool stroke. The activated teeth ABT increases as the stroke length increases, thereby increasing the life of the saw blade 104 as the wear on the teeth is more evenly distributed along the teeth.

[0100] Figures 25A-25C The saw blade 104 cutting the workpiece 134 is shown. In the illustrated configuration, the saw blade 104 is coupled to the saw 100 with a stroke length of 1.25 inches. In the illustrated configuration, the beam thickness X9 is 1.5 inches. Figure 25A The saw blade 104 in the FDC position in contact with the workpiece 134 before cutting begins is shown. The first section 408 of the saw blade 104 contacts the entire beam thickness X9. The second section 412 of the saw blade 104 represents the portion of the saw blade 104 that will contact the workpiece 134 as the saw blade reciprocates from the FDC position to the BDC position (i.e., reverse stroke).

[0101] Figure 25BThe saw blade 104 is shown in the BDC position. As noted above, the second segment 412 is now in full contact with the workpiece 134. However, since the stroke length is 1.25 inches and the overall beam thickness is 1.5 inches, the third segment 416 of the saw blade 104 is still in contact with the workpiece 134. In other words, the third segment 416 has not exited the cutting plane Y3 since the saw 100 does not have enough stroke length. The third segment 416 is the portion of the first segment 408 that has not exited the cutting plane Y3. Since the third segment 416 has not exited the cutting plane Y3, the chips formed by the reverse stroke provided in the third segment 416 are not ejected because the third segment 416 has not exited the cutting plane Y3. The chips occupying the third segment 416 reduce the performance of the third segment 416 of the saw blade 104 in subsequent strokes.

[0102] Figure 25C The saw blade 104 is shown returning from the BDC position to the FDC position after a forward stroke. The first segment 408 has resumed full contact with the cutting plane Y3. The second segment 412 is fully out of the cutting plane Y3. The third segment 416 remains in contact with the cutting plane Y3, preventing the ejection of chips in the third segment 416.

[0103] Figures 26A-26C The saw blade 104 is shown cutting the workpiece 134. In the illustrated configuration, the saw blade 104 is coupled to the saw 100 having a stroke length of 1.5 inches. In the illustrated configuration, the beam thickness X9 is 1.5 inches. Figure 26A The saw blade 104 is shown in the FDC position contacting the workpiece 134 prior to the start of the cut. Figures 26A to 26B The saw blade 104 is shown in the BDC. That is, the saw has completed a reverse stroke from the FDC position. Figure 26C The stroke length matches or exceeds the beam thickness X9. The first segment 408 is fully out of the cutting plane Y3. As such, the chips accumulated in the first segment 408 are ejected as the first segment 408 exits the cutting plane Y3. Figure 25B The saw blade 104 is shown returning from the BDC position to the FDC position after a forward stroke. The ejection of the chip core from the first segment 408 prevents a reduction in performance due to chips trapped in the first segment 408 (e.g., ​ and 25C the third segment 416).

[0104] The various features of the present invention are recited in the appended claims.

Claims

1. A reciprocating saw, characterized in that, include: case; An electric motor, the electric motor being positioned within the housing and having a motor output shaft rotatable about a motor axis; Spindle assembly, including: Main spindle frame, pivotally coupled to the housing about a pivot joint defining a pivot axis, and A spindle, the spindle being supported for reciprocating within the spindle frame along a spindle axis oriented perpendicular to the pivot axis, wherein the spindle reciprocates along the spindle axis between a rear dead center (BDC) position and a front dead center (FDC) position, the spindle including a saw blade connection portion configured to fix a saw blade, the saw blade connection portion defining a saw blade connection axis parallel to the pivot axis; A track plate configured to convert torque from the motor output shaft into reciprocating motion of the main shaft, the track plate including a cam surface about a rotation axis of the track plate; An eccentric drive member coupled to the track plate for rotation therewith, the eccentric drive member having an eccentric portion offset from the rotation axis of the track plate, the eccentric portion being coupled to the spindle to reciprocate the spindle in response to rotation of the eccentric drive member and the track plate; and A follower, coupled to the spindle assembly and engaging a cam surface on the track plate, pivots the spindle frame about the pivot axis in response to rotation of the track plate, thereby causing the spindle to move along a track. The cam surface includes a high-frequency segment occupying less than 180 degrees of the circumference of the cam surface. Specifically, when the spindle is at the front dead center (FDC) position, the displacement of the saw blade connecting axis in the direction perpendicular to the spindle axis is zero. The total displacement of the saw blade connecting axis in a direction perpendicular to the spindle axis occurs during the forward stroke when the spindle travels from the rear dead center (BDC) position to the front dead center (FDC) position and during the reverse stroke when the spindle travels from the front dead center (FDC) position to the rear dead center (BDC) position. The high-frequency section is configured to cause the saw blade connecting axis to shift between 80% and 100% of the total displacement.

2. The reciprocating saw as described in claim 1, characterized in that, The high-frequency section occupies 90 degrees of the circumference of the cam surface.

3. The reciprocating saw as described in claim 1, characterized in that, The spindle assembly includes a first bushing and a second bushing, the first bushing being configured to support the spindle in reciprocating motion, the second bushing being configured to support the spindle in reciprocating motion, wherein the spindle frame receives the first bushing and the second bushing, and wherein the spindle frame is a single piece.

4. The reciprocating saw as described in claim 1, characterized in that, It further includes a counterweight, wherein the counterweight is configured to reciprocate in a direction parallel to the axis of the main shaft.

5. The reciprocating saw as described in claim 1, characterized in that, The cam surface has a phase angle of 0 degrees at the front dead center (FDC) position, wherein the cam surface has a phase angle of 180 degrees at the rear dead center (BDC) position, wherein the high-frequency segment occupies the circumference of the cam surface between a first point and a second point, wherein the phase angle of the cam surface is 150 degrees when the follower engages the first point.

6. A reciprocating saw, characterized in that, include: case; An electric motor, the electric motor being positioned within the housing and having a motor output shaft rotatable about a motor axis; Spindle assembly, the spindle assembly comprising: A main spindle frame, pivotally coupled to the housing about a pivot joint defining a pivot axis, and A spindle, the spindle being supported for reciprocating within the spindle frame along a spindle axis oriented perpendicular to the pivot axis, wherein the spindle reciprocates along the spindle axis between a rear dead center (BDC) position and a front dead center (FDC) position; A track plate configured to convert torque from the motor output shaft into reciprocating motion of the main shaft, the track plate including a cam surface about a rotation axis of the track plate; An eccentric drive member coupled to the track plate for rotation therewith, the eccentric drive member having an eccentric portion offset from the rotation axis of the track plate, the eccentric portion having an eccentric pin coupled to the spindle to reciprocate the spindle in response to rotation of the eccentric drive member and the track plate; and A follower, coupled to the spindle assembly and engaging the cam surface on the track plate, pivots the spindle frame about the pivot axis in response to rotation of the track plate, thereby causing the spindle to move along the track. The cam surface includes a high-frequency segment that spans the circumference of the cam surface between a first point and a second point. The cam surface includes a low-frequency segment that spans the remainder of the circumference of the cam surface. The spindle has a defined positive travel distance when moving from the rear dead center (BDC) position to the front dead center (FDC) position. Wherein, the spindle defines a reverse travel when moving from the front dead center (FDC) position to the rear dead center (BDC) position, and wherein, at the first rotational position of the track plate, the follower engages the first point, and wherein, at the first rotational position, the eccentric pin is angularly offset from the first point relative to the axis of rotation at an angle between -180 degrees and 180 degrees.

7. The reciprocating saw as described in claim 6, characterized in that, The included angle is 30 degrees.

8. The reciprocating saw as described in claim 6, characterized in that, The spindle assembly includes a first bushing and a second bushing, the first bushing being configured to support the spindle in reciprocating motion, the second bushing being configured to support the spindle in reciprocating motion, the spindle frame receiving the first bushing and the second bushing, and wherein the spindle frame is a single piece.

9. The reciprocating saw as described in claim 6, characterized in that, This further includes counterweights.

10. The reciprocating saw as described in claim 9, characterized in that, The counterweight is configured to reciprocate in a direction parallel to the axis of the main shaft.

11. A reciprocating saw, characterized in that, include: case; An electric motor, the electric motor being positioned within the housing and having a motor output shaft rotatable about a motor axis; Spindle assembly, the spindle assembly comprising: A main spindle frame, pivotally coupled to the housing about a pivot joint defining a pivot axis, and A spindle, which is supported for reciprocating motion within the spindle frame along a spindle axis oriented perpendicular to the pivot axis; A transmission member configured to receive torque from the motor output shaft, such that the transmission member rotates about a rotation axis; An eccentric drive member coupled to the transmission member to rotate together therewith, the eccentric drive member having an eccentric portion offset from the axis of rotation of the transmission member, the eccentric portion being coupled to the spindle to cause the spindle to reciprocate in response to rotation of the eccentric drive member and the transmission member about the axis of rotation; A cam surface, the cam surface about the rotation axis of the transmission member; and A follower, coupled to the spindle assembly and engaging the cam surface, causes the spindle frame to pivot about the axis of rotation in response to rotation of the cam surface about the axis of rotation, thereby producing orbital motion of the spindle. The cam surface includes a first segment and a second segment, the first segment having a first waveform, and the second segment having a second waveform different from the first waveform.

12. The reciprocating saw as described in claim 11, characterized in that, The first segment defines a first angular span, and the second segment defines a second angular span, wherein the first angular span is smaller than the second angular span.

13. The reciprocating saw as described in claim 12, characterized in that, The first angle spans 90 degrees.

14. The reciprocating saw as described in claim 12, characterized in that, The spindle reciprocates between a rear dead center (BDC) position and a front dead center (FDC) position along the spindle axis, wherein the spindle includes a saw blade connection portion configured to fix a saw blade, the saw blade connection portion defining a saw blade connection axis parallel to the pivot axis, wherein when the spindle is at the front dead center (FDC) position, the displacement of the saw blade connection axis relative to a direction perpendicular to the spindle axis is zero, wherein the phase angle of the cam surface at the front dead center (FDC) position is 0 degrees, and wherein the phase angle of the cam surface at the rear dead center (BDC) position is 180 degrees.

15. The reciprocating saw as described in claim 14, characterized in that, As the spindle travels from the front dead center (FDC) position to the rear dead center (BDC) position, the saw blade connecting axis moves in the reverse direction in a first direction perpendicular to the spindle axis, wherein the maximum reverse displacement of the saw blade connecting axis in the first direction occurs when the phase angle is 150 degrees.

16. The reciprocating saw as described in claim 15, characterized in that, As the spindle travels from the rear dead center (BDC) position to the front dead center (FDC) position, the saw blade connecting axis moves in a positive direction perpendicular to the spindle axis, the second direction being opposite to the first direction, wherein the maximum positive displacement in the second direction occurs when the phase angle is 240 degrees.

17. The reciprocating saw as described in claim 11, characterized in that, The spindle assembly includes a first bushing and a second bushing, the first bushing being configured to support the spindle in reciprocating motion, the second bushing being configured to support the spindle in reciprocating motion, wherein the spindle frame receives the first bushing and the second bushing, and wherein the spindle frame is a single piece.

18. The reciprocating saw as described in claim 11, characterized in that, This further includes counterweights.

19. The reciprocating saw as described in claim 18, characterized in that, The counterweight is configured to reciprocate in a direction parallel to the axis of the main shaft.

20. The reciprocating saw as described in claim 11, characterized in that, The reciprocating saw includes a drive pinion coupled to rotate with the motor output shaft, wherein the transmission member meshes with the drive pinion.

21. The reciprocating saw as described in claim 11, characterized in that, The transmission component is rotatably supported by an intermediate shaft coaxial with the rotation axis.

22. The reciprocating saw as described in claim 11, characterized in that, The axis of rotation is perpendicular to the axis of the motor.

23. The reciprocating saw as described in claim 11, characterized in that, The driven component is a roller bearing supported at the rear end of the main shaft frame.

24. The reciprocating saw as described in claim 11, characterized in that, It further includes a biasing member positioned between the spindle frame and the housing, the biasing member being configured to apply a restoring torque about the pivot axis.

25. A reciprocating saw, characterized in that, include: case; An electric motor, the electric motor being positioned within the housing and having a motor output shaft rotatable about a motor axis; Spindle assembly, including: A main spindle frame, pivotally coupled to the housing about a pivot joint defining a pivot axis, and A spindle, which is supported for reciprocating motion within the spindle frame along a spindle axis oriented perpendicular to the pivot axis; A transmission member configured to receive torque from the motor output shaft, such that the transmission member rotates about a rotation axis; An eccentric drive member coupled to the transmission member to rotate together with it, the eccentric drive member being offset from the axis of rotation of the transmission member by a distance greater than 0.625 inches and less than or equal to 0.75 inches, the eccentric drive member being coupled to the spindle to cause the spindle to reciprocate in response to rotation of the eccentric drive member and the transmission member about the axis of rotation; A cam surface, the cam surface about the rotation axis of the transmission member; and A follower, coupled to the spindle assembly and engaging the cam surface, causes the spindle frame to pivot about the axis of rotation in response to rotation of the cam surface about the axis of rotation, thereby causing the spindle to move in an orbit.

26. The reciprocating saw as described in claim 25, characterized in that, The cam surface includes a first segment and a second segment, the first segment having a first waveform, and the second segment having a second waveform different from the first waveform.

27. The reciprocating saw as described in claim 26, characterized in that, The first segment defines a first angular span, wherein the second segment defines a second angular span, wherein the first angular span is smaller than the second angular span.

28. The reciprocating saw as described in claim 27, characterized in that, The first angle spans 90 degrees.

29. The reciprocating saw as described in claim 27, characterized in that, The spindle reciprocates along its axis between a rear dead center (BDC) position and a front dead center (FDC) position, wherein the spindle includes a saw blade connection portion configured to fix a saw blade, the saw blade connection portion defining a saw blade connection axis parallel to the pivot axis, wherein when the spindle is at the front dead center (FDC) position, the displacement of the saw blade connection axis relative to a direction perpendicular to the spindle axis is zero, wherein the total displacement of the saw blade connection axis in the direction perpendicular to the spindle axis occurs during the forward travel of the spindle from the rear dead center (BDC) position to the front dead center (FDC) position and the reverse travel of the spindle from the front dead center (FDC) position to the rear dead center (BDC) position, and wherein the first segment is configured to displace between 80% and 100% of the total displacement.

30. The reciprocating saw as described in claim 27, characterized in that, The first angular span is between a first point and a second point, wherein the spindle reciprocates along the spindle axis between a rear dead center (BDC) position and a front dead center (FDC) position, wherein the spindle defines a forward stroke when moving from the rear dead center (BDC) position to the front dead center (FDC) position, wherein the spindle defines a reverse stroke when moving from the front dead center (FDC) position to the rear dead center (BDC) position, and wherein at a first rotational position of the transmission member, the driven member engages the first point, and wherein at the first rotational position, the eccentric drive member is angularly offset from the first point relative to the axis of rotation at an angle between -180 degrees and 180 degrees.

31. The reciprocating saw as described in claim 30, characterized in that, The included angle is 30 degrees.

32. A reciprocating saw, characterized in that, include: case; An electric motor, the electric motor being positioned within the housing and having a motor output shaft rotatable about a motor axis; Spindle assembly, the spindle assembly comprising: A main spindle frame, pivotally coupled to the housing about a pivot joint defining a pivot axis, and A spindle, the spindle being supported for reciprocating within the spindle frame along a spindle axis oriented perpendicular to the pivot axis, wherein the spindle reciprocates along the spindle axis between a rear dead center (BDC) position and a front dead center (FDC) position, the spindle including a saw blade connection portion configured to fix a saw blade, the saw blade connection portion defining a saw blade connection axis parallel to the pivot axis; A track plate configured to convert torque from the motor output shaft into reciprocating motion of the main shaft, the track plate including a cam surface about a rotation axis of the track plate; An eccentric drive member coupled to the track plate for rotation therewith, the eccentric drive member having an eccentric portion offset from the rotation axis of the track plate, the eccentric portion being coupled to the spindle to reciprocate the spindle in response to rotation of the eccentric drive member and the track plate; and A follower, coupled to the spindle assembly and engaging a cam surface on the track plate, pivots the spindle frame about the pivot axis in response to rotation of the track plate, thereby causing the spindle to move along a track. The cam surface includes a high-frequency segment occupying less than 180 degrees of the circumference of the cam surface. When the spindle is at the front dead center (FDC) position, the displacement of the saw blade connecting axis in the direction perpendicular to the spindle axis is zero. When the spindle travels from the rear dead center (BDC) position to the front dead center (FDC) position, the maximum positive displacement of the saw blade connecting axis in the direction perpendicular to the spindle axis occurs during the forward stroke. The phase angle of the cam surface at the front dead center (FDC) position is 0 degrees. The phase angle of the cam surface at the rear dead center (BDC) position is 180 degrees, and The phase angle of the cam surface at the maximum positive displacement is between 200 degrees and 280 degrees.

33. The reciprocating saw as described in claim 32, characterized in that, The maximum reverse displacement of the saw blade connecting axis in the direction perpendicular to the spindle axis occurs during the reverse stroke of the spindle as it moves from the front dead center (FDC) position to the rear dead center (BDC) position, and wherein the phase angle of the cam surface at the maximum reverse displacement is between 110 degrees and 190 degrees.

34. The reciprocating saw as described in claim 33, characterized in that, The total displacement is the sum of the maximum forward displacement and the maximum reverse displacement, wherein the total displacement is between 0.03 inches and 0.11 inches.

35. The reciprocating saw as described in claim 33, characterized in that, The high-frequency section occupies 90 degrees of the circumference of the cam surface, wherein the total displacement is the sum of the maximum forward displacement and the maximum reverse displacement, and wherein the high-frequency section is configured to displace the saw blade connecting axis between 80% and 100% of the total displacement.

36. The reciprocating saw as described in claim 32, characterized in that, The high-frequency segment occupies the circumference of the cam surface between a first point and a second point on the cam surface, wherein when the follower engages the first point, the phase angle of the cam surface is 150 degrees.

37. The reciprocating saw as described in claim 32, characterized in that, It further includes a counterweight, wherein the counterweight is configured to reciprocate in a direction parallel to the axis of the main shaft.

38. A reciprocating saw, characterized in that, include: case; An electric motor, the electric motor being positioned within the housing and having a motor output shaft rotatable about a motor axis; Spindle assembly, including: A main spindle frame, pivotally coupled to the housing about a pivot joint defining a pivot axis, and A spindle, which is supported for reciprocating motion within the spindle frame along a spindle axis oriented perpendicular to the pivot axis; A transmission member configured to receive torque from the motor output shaft, such that the transmission member rotates about a rotation axis; An eccentric drive member coupled to the transmission member to rotate together with it, the eccentric drive member having an eccentric portion offset from the rotation axis of the transmission member, the eccentric portion being coupled to the spindle to cause the spindle to reciprocate in response to rotation of the eccentric drive member and the transmission member about the rotation axis; A cam surface, the cam surface about the rotation axis of the transmission member; and A follower, coupled to the spindle assembly and engaging the cam surface, causes the spindle frame to pivot about the axis of rotation in response to rotation of the cam surface about the axis of rotation, thereby producing orbital motion of the spindle. The cam surface includes a first segment and a second segment, the first segment defining a first average slope and the second segment defining a second average slope, and The first average slope is greater than the second average slope.

39. The reciprocating saw as described in claim 38, characterized in that, The first segment defines a first angular span, wherein the second segment defines a second angular span, the second angular span spanning the remainder of the periphery of the cam surface, wherein the first angular span is smaller than the second angular span.

40. The reciprocating saw as described in claim 39, characterized in that, The first angle spans 90 degrees.

Images