Abstract:
A power tool includes a housing having a handle configured for a user, the handle defining a first axis, a motor supported by the housing, the motor defining a second axis along a length of the motor, a tool element movably supported by the housing and drivingly coupled to the motor, the tool element defining a third axis along a length of the tool element. Each of the first, second, and third axes are oblique with respect to each of the other axes.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present patent application is a continuation of U.S. patent application Ser. No. 12/399,839, filed Mar. 6, 2009, which claims priority to U.S. Provisional Patent Application Ser. No. 61/034,816, titled “PORTABLE BATTERY-POWERED RECIPROCATING SAW” and filed on Mar. 7, 2008 by Daniel J. Alberti, John S. Scott, Michael S. Steele, Roger D. Neitzell, and Michael Naughton, the entire contents of which is hereby incorporated by reference. 
    
    
     BACKGROUND 
     The present invention relates to a reciprocating saw, and, more particularly, to a portable, battery powered reciprocating saw. 
     Reciprocating saws are used to cut a variety of objects made from a variety of materials, such as metal pipes, wood and dry wall. A cordless, compact reciprocating saw allows for cutting operations in tight spaces or awkward angles for plumbing, electrical, remodeling and HVAC applications. 
     SUMMARY 
     In one embodiment, the invention provides a power tool. The power tool includes a housing having a handle configured for a user, the handle defining a first axis. A motor supported by the housing, the motor defining a second axis along a length of the motor. A tool element movably supported by the housing and drivingly coupled to the motor, the tool element defining a third axis along a length of the tool element. Each of the first, second, and third axes are oblique with respect to each of the other axes. 
     In another embodiment, the invention provides a reciprocating saw. The reciprocating saw includes a housing having a handle configured for a user to grasp, the handle defining a first axis. A motor supported by the housing, the motor defining a second axis along a length of the motor. A spindle movably supported by the housing and drivingly coupled to the motor, the spindle having an end adapted to support a saw blade and defining a third axis along a length of the spindle. Each of the first, second, and third axes are non-parallel with respect to each of the other axes. 
     In yet another embodiment, the invention provides a reciprocating saw. The reciprocating saw includes a housing having a battery cavity adapted to receive a battery, the housing defining a first axis along which the battery is received in the housing. A motor supported by the housing, the motor defining a second axis along a length of the motor. A spindle movably supported by the housing and drivingly coupled to the motor, the spindle having an end adapted to support a saw blade and defining a third axis along a length of the spindle. The first axis is at a first angle with respect to the second axis and the second axis is at a second angle with respect to the third axis. 
     In yet another embodiment, the invention provides a power tool. The power tool includes a housing including a boss and a battery cavity adapted to receive a battery, a motor supported by the housing, a tool element drivingly coupled to the motor, a drive system operable to drive the tool element, a gear case substantially enclosing the drive system, wherein the gear case includes a tab having an aperture for receiving the boss of the housing, and a fastener extending through the boss to couple the gear case to the housing. The boss electrically isolates the gear case from the fastener. 
     In yet another embodiment, the invention provides a power tool. The power tool includes a housing including a handle portion, the housing formed from a first housing portion and a second housing portion, each housing portion including a boss, wherein the boss of the first housing portion substantially aligns with the boss on the second housing portion. The power tool further includes a motor supported by the housing, a tool element drivingly coupled to the motor, a drive system coupling the motor to the tool element, the drive system operable to drive the tool element, a gear case substantially enclosing the drive system, the gear case including a tab with an aperture, wherein the aperture of the tab receives at least one of the bosses, and a fastener extends through the bosses to couple the gear case to the housing. The bosses electrically isolate the gear case from the fastener. 
     In yet another embodiment, the invention provides a reciprocating saw. The reciprocating saw includes a housing including a handle portion, the housing formed from a first housing portion and a second housing portion, each housing portion including a boss, wherein the boss of the first housing portion substantially aligns with the boss on the second housing portion. The reciprocating saw further includes a motor supported by the housing, a spindle movably supported by the housing and drivingly coupled to the motor, the spindle having an end adapted to support a saw blade, a drive system coupling the motor to the spindle, the drive system operable to drive the spindle, a gear case substantially enclosing the drive system, the gear case including a tab with an aperture, wherein the aperture of the tab receives at least one of the bosses, and a fastener extends through the bosses to couple the gear case to the housing. The bosses electrically isolate the gear case from the fastener. 
     Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a portable battery-powered reciprocating saw according to an embodiment of the invention. 
         FIG. 1   a  is a perspective view of the portable battery-powered reciprocating saw shown in  FIG. 1  with a blade and battery pack removed. 
         FIG. 2  is another perspective view of the portable reciprocating saw shown in  FIG. 1   a.    
         FIG. 3  is a side view of the portable reciprocating saw shown in  FIG. 1   a.    
         FIG. 4  is another side view of the portable reciprocating saw shown in  FIG. 1   a.    
         FIG. 5  is a front view of the portable reciprocating saw shown in  FIG. 1   a.    
         FIG. 6  is a rear view of the portable reciprocating saw shown in  FIG. 1   a.    
         FIG. 7  is a cross section view of the portable reciprocating saw shown in  FIG. 1   a.    
         FIG. 8  is an exploded view of the portable reciprocating saw shown in  FIG. 1   a.    
         FIG. 9  is a detailed view of a portion of the gear case and housing of the portable reciprocating saw shown in  FIG. 1   a.    
     
    
    
     Before at least one embodiment of the invention is explained in detail, it is to be understood that the invention is not limited it its application to the details of the construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practices or carried out in various ways. In addition, it is understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. 
     DETAILED DESCRIPTION 
     A portable hand tool  20  or a portable reciprocating saw is shown in  FIGS. 1-9 . In these constructions, the saw  20  is a battery-powered reciprocating saw. In the illustrated constructions, the saw  20  is powered by a power tool battery pack  25 . The battery pack  25  may be configured to connect and power a variety of tools in addition to the reciprocating saw  20 . In the construction shown, the battery pack  25  is a 12V lithium-ion battery pack. The pack  25  includes three (3) battery cells (not shown) connected in series. In other embodiments, the battery pack  25  may include fewer or more battery cells, such that the battery pack  25  is a 14.4-volt power tool battery pack, an 18-volt power tool battery pack, or the like. Additionally or alternatively, the battery cells may have chemistries other than lithium-ion such as, for example, nickel cadmium, nickel metal-hydride, or the like. In still other constructions, the saw  20  may be a corded power tool. In other embodiments, the power tool may be another hand-held power tool, such as, for example, another type of reciprocating power tool, a drill, a screwdriver, or other handheld power tool. 
     The saw  20  includes a housing  40 . As shown in  FIG. 8 , the housing  40  has a first housing portion  42  and a second housing portion  44 . Each housing portion  42 ,  44  is formed of plastic; however, in some embodiments, the housing portions  42 ,  44  may be formed of other materials. In the construction shown, bosses  330  are formed in both housing portions  42 ,  44 . Each boss  330  includes an aperture  332 , and each aperture  332  extends through each housing portion  42 ,  44 . When the housing portions  42 ,  44  are assembled, the apertures  332  from the first housing portion  42  generally align with the apertures  332  from the second housing portion  44 . In some constructions, the bosses  330  from the first housing portion  42  align with and are in physical contact with the bosses  330  formed in the second housing portion  44 . In other constructions, the bosses  330  may be adjacent to respective bosses  330 , although not in physical contact with each other. In some constructions, the bosses  330  may be of the same height. In other constructions, the bosses  330  may be of different height, such that to engage with each other, bosses  330  on one of the housing portions  42 ,  44  extend further than the bosses  330  on the other of the housing portions  42 ,  44  (e.g., beyond a interface line between the housing portions  42 ,  44 ). 
     The housing  40  defines a handle housing portion  45 , a motor housing portion  50  and a gear case housing portion  55 . The handle housing portion  45  includes at least one grip surface  48  for a user to grasp. In the illustrated constructions, the handle housing portion  45  can also define a battery receiving portion  60  ( FIGS. 2 and 6 ) for receiving the battery pack  25 . In other constructions, the battery receiving portion  60  may be defined elsewhere within the housing  40 . The motor housing portion  50  supports a motor  65  ( FIGS. 7 and 8 ), and the gear case housing portion  55  in turn supports a gear case  68  ( FIGS. 7 and 8 ). 
     As shown in  FIG. 1 , the battery receiving portion  60  is configured as a cavity. When the battery pack  25  is connected to the saw  20 , the pack  25  is inserted into the cavity  60  and substantially closes the cavity  60 . A terminal block  70  ( FIG. 6 ) is positioned in the cavity  60 . The terminal block  70  includes a positive terminal  75 , a negative terminal  80  and a sense terminal  85 . The terminals  75 ,  80  electrically connect the battery pack  25  to the motor  65 . The sense terminal  85  electrically connects the battery pack  25  to a monitoring circuit  105 , which is discussed below. 
     As shown in  FIGS. 2-4  and  7 , a switch  90  is positioned on the handle housing portion  45  for powering the saw  20 . As illustrated, the switch  90  is an on/off trigger switch. In other embodiments, the switch  90  may be a variable speed trigger switch, a two speed trigger switch, a push button or other actuator. 
     A fuel gauge  100  is positioned on the motor housing portion  50  just above the handle housing portion  45 , as shown in  FIG. 4 . The fuel gauge  100  is activated and controlled by the monitoring circuit  105 . The circuit  105  is positioned within the housing  40  and communicates with the battery pack  25 . The monitoring circuit  105  periodically senses the state of charge of the battery pack  25  via the sense terminal  85  and displays the remaining state of charge to the user with a visual indication via the fuel gauge  100 . For example, in the illustrated construction, the fuel gauge  100  includes four (4) LEDs. To display 100% state of charge remaining in the pack  25 , the circuit  105  would activate all four (4) LEDs. To display 75% state of charge remaining, the circuit  105  would activate three (3) LEDs. For 50% state of charge remaining, two (2) LEDs would be activated, and for 25% state of charge remaining, one (1) LED would be activated. To display 10% state of charge remaining or a low state of charge warning, one (1) LED would be flashing. 
     In the construction shown, the fuel gauge  100  is activated when the user actuates the switch  90 . In other constructions, the fuel gauge  100  may be activated when the user actuates a secondary switch (not shown), such as a push button. 
     Referring to  FIGS. 7-9 , the gear case  68  encloses a drive system  205  for the saw  20 . In this construction, the drive system  205  is a scotch yoke mechanism. The drive system  205  includes a driving gear  210 , a driven gear  215 , a pin  225  connected to the driven gear  215 , and a yoke  230 . In this construction, the driving gear  210  is a spiral bevel pinion and the driven gear  215  is a spiral bevel gear. The yoke  230  is connected to a spindle assembly  235 . The spindle assembly  235  includes a spindle shaft  240  and a blade clamp  260 . As shown in  FIG. 1 , a tool element  250 , such as a blade, is coupled to the spindle shaft  240  via the blade clamp  260 . In the construction shown, the blade clamp  260  includes the blade clamp assembly shown and described in U.S. Pat. No. 6,725,548, entitled “Keyless Blade Clamp Mechanism” and issued Apr. 27, 2004, the contents of which are hereby incorporated by reference. The blade clamp  260  can also be configured to accept a variety of reciprocating saw blades, jig saw blades and/or hack saw blades. 
     In operation, the pinion  210  is coupled directly to the output shaft of the motor  65 . As the output shaft rotates, the pinion  210  rotates and engages teeth of the spiral bevel gear  215  to rotate the gear  215 . As the spiral bevel gear  215  rotates, the pin  225  coupled to the gear  215  also rotates. The yoke  230  includes a shaft  245  that surrounds the pin  225  of the gear  215 . Thereby, the yoke  230  translates back and forth due to the pin  225  rotating within the shaft  245 . The yoke  230  in turn translates the spindle  240  in the desired reciprocating motion. 
     The gear case  68  also includes a first case portion  305  and a second case portion  310 . In the construction shown, the gear case portions  305 ,  310  are metal cases. When assembled, gear case portions are secured via fasteners  315 . In the construction shown, each portion  305 ,  310  includes one or more tabs or hoops  320 . Each tab  320  includes an aperture  325  that extends through the tab  320 , such that the apertures  325  align with and/or receive the bosses  330  formed in the housing portions  42 ,  44 . In other constructions, the tabs or hoops  320  can be positioned on just one gear case portion, such as, for example, the first case portion  305 , but not positioned on the other gear case portion, such as, for example, the second case portion  310 . In further constructions, the tabs  320  can be formed on each gear case portion  305 ,  310 . However, the tabs  320  positioned on the first case portion  305  may not align with the tabs  320  positioned on the second case portion  310 . In this construction, the tabs  320  positioned on the first case portion  305  will only align with some of the bosses  330 , while the tabs  320  positioned on the second case portion  310  will only align with the remaining bosses  330 . In still further constructions, the tabs  320  can be configured in a different shape or manner. 
     As shown in  FIG. 9 , when the saw  20  is assembled, each of the bosses  330  formed in the housing portions  42 ,  44  align with one of the apertures  325  of the respective tab  320  formed in the gear case  68 . Further, each of the bosses  330  formed in the first housing portion  42  substantially align in the tabs  320  with the bosses  330  formed in the second housing portion  44 . The bosses  330  at least partially extend through the tabs  320 , such that the tab  320  surrounds a portion of at least one of the bosses  330 . In some constructions, the bosses  330  from each housing portion  42 ,  44  contact each other within the tab  320 . However, in other constructions, the bosses  330  from each housing portion  42 ,  44  may be adjacent, although not in physical contact, with each other. In other constructions, the bosses  330  may be of different height, such that to engage with each other, bosses  330  on one of the housing portions  42 ,  44  extend further than the bosses  330  on the other of the housing portions  42 ,  44 . 
     Fasteners  340  are inserted into the bosses  330  to couple the first housing portion  42  to the second housing portion  44  and further secure the gear case  68  within the housing  40 . Since the fasteners  340  reside within the bosses  330 , the fasteners  340  are electrically isolated from the gear case  68 , including the drive system  205  and spindle shaft  240  that are contained in the gear case  68 , and thereby the gear case  68  is electrically isolated within the housing  40  and from the rest of saw  20 . 
     The saw  20  also includes a shoe assembly  350 . In the construction shown, the shoe assembly  350  is a fixed shoe assembly. The shoe assembly  350  includes a front surface or plate  360  which engages or rests on a workpiece. As shown in  FIGS. 3 ,  4  and  7 , the front surface  360  is slightly curved outward from the saw  20 , or non-planar. The front surface  360  is curved such that any three points on the front surface  360  lying in a plane parallel to a center plane (coplanar with axis  420 ) of saw  20  defines an arc or radius of curvature of approximately 170 mm. In other constructions (not shown), the plate  360  may have a radius greater than or less than 170 mm. The front plate  360  also defines an opening  365  for the saw blade  250  to pass through. The shoe assembly  350  further includes a top portion  395  coupled to the top of the front surface  360  and lying outside of the 170 mm arc. The shoe assembly  350  also includes two connecting members  370  for connecting the shoe assembly  350  to the housing  40 . In other constructions (not shown), the shoe assembly  350  may be an adjustable shoe assembly or a pivoting shoe assembly. 
     As shown in  FIG. 7 , the battery pack  25  is inserted into the battery cavity  60  of the saw  20  along a handle axis  400 , which also defines a battery insertion axis. The motor  65  is positioned within the housing  40  and defines a longitudinal motor axis  410  along a length of the motor  65 . The gear case is also positioned along the motor axis  410 . The spindle  240  and the saw blade  250  are positioned along a longitudinal spindle axis  420  defined along a length of the spindle  240  and saw blade  250 . The reciprocating motion of the spindle  240  translates back and forth along the spindle axis  420 . 
     The axes  400 ,  410 ,  420  are positioned such that each axis  400 ,  410 ,  420  is oblique, or not otherwise perpendicular and/or parallel with respect to the other axes. More specifically, the handle axis  400  is positioned at an angle α with respect to the motor axis  410 , the motor axis  410  is positioned at an angle θ with respect to the spindle axis  420 , and the spindle axis  420  is positioned at an angle β with respect to the handle axis  400 . In some embodiments, each of the axes  400 ,  410 ,  420  may be either non-parallel or non-orthogonal with respect to each of the other axes  400 ,  410 ,  420 . 
     In the illustrated construction and referring to  FIG. 7 , each of the axes  400 ,  410 ,  420  is oblique with respect to the other axes  400 ,  410 ,  420 . Angle α is an angle defined between the handle axis  400  and the motor axis  410  and is in a range of approximately 50 degrees to 70 degrees. In the illustrated construction, angle α is 60 degrees. In still other constructions, angle α may be greater than 70 degrees or less than 50 degrees. Angle θ is an angle defined between the motor axis  410  and the spindle axis  420  and is in a range of approximately 110 degrees to 130 degrees. In the illustrated construction, angle θ is approximately 120 degrees. In other constructions, angle θ may be greater than 130 degrees or less than 110 degrees. Angle β is an angle defined between the handle axis  400  and the spindle axis  420  and is in a range of approximately 150 degrees to 170 degrees. In the illustrated construction, angle β is approximately 161.7 degrees. In other constructions, angle β is greater than 170 degrees or less than 150 degrees. 
     The position of the axes, the size of the tool, and other characteristics are designed for optimal cutting application for the saw  20 , including but not limited to PVC cutting, dry wall cutting, light metal cutting, EMT or thin wall conduit cutting and the like. For example, the orientation of motor  65  along motor axis  410  allows the saw  20  to be more compact by reducing the overall length of saw  20  as compared to the length of a conventional saw. Saw  20  is also ergonomically designed such that the longitudinal axis  400  is positioned for optimal user operation related to handle grip location and angle for performing a cutting operation. 
     Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of one or more independent aspects of the invention as described.