Reciprocating saw
A power tool includes a housing, a motor, and a drive mechanism. The drive mechanism includes a driven gear that is rotated by the motor. The driven gear is vertically-oriented within the housing and has an upper portion and a lower portion. The drive mechanism also includes a connecting rod coupled to the driven gear to translate rotary motion of the driven gear into reciprocating motion, and an output shaft coupled to the connecting rod to reciprocate relative to the housing through a cutting stroke and a return stroke. The drive mechanism further includes a counterweight coupled to the driven gear for rotation with the driven gear. The counterweight moves through the upper portion of the driven gear during the cutting stroke of the output shaft, and moves through the lower portion of the driven gear during a return stroke of the output shaft.
1. A reciprocating saw comprising:
a housing;
a motor positioned within the housing, the motor including a pinion rotatable about a motor axis; and
a drive mechanism positioned within the housing and coupled to the motor, the drive mechanism including
a driven gear that engages the pinion and is rotated by the motor, the driven gear having a circumference and being vertically-oriented within the housing with the motor axis extending through a center of the driven gear,
a connecting rod coupled to the driven gear to translate rotary motion of the driven gear into reciprocating motion,
an output shaft coupled to the connecting rod to reciprocate relative to the housing through a cutting stroke and a return stroke, the output shaft configured to support a tool element, and
a counterweight coupled to the driven gear and rotating with the driven gear through a path and in a same rotational direction, the counterweight travelling above the motor axis during the cutting stroke of the output shaft, and travelling below the motor axis during the return stroke of the output shaft, the counterweight including a connection portion coupled to the connecting rod and a mass portion including a leading edge, a trailing edge, and a curved outer perimeter matching the circumference of the driven gear, the curved outer perimeter extending more than 90 degrees between the leading and trailing edges.
2. The reciprocating saw of claim 1 , wherein the driven gear is rotated by the motor in the rotational direction about a central axis that is perpendicular to the motor axis.
3. The reciprocating saw of claim 2 , wherein the output shaft reciprocates along a spindle axis, wherein the motor axis and the spindle axis define a plane, and wherein the driven gear rotates about the central axis perpendicular to the plane.
4. The reciprocating saw of claim 3 , wherein the central axis intersects the motor axis.
5. The reciprocating saw of claim 3 , wherein the spindle axis is generally parallel to the motor axis.
6. The reciprocating saw of claim 1 , wherein the mass portion includes an aperture positioned closer to the trailing edge than to the leading edge in the rotational direction.
7. The reciprocating saw of claim 1 , wherein the pinion is positioned between the driven gear and the counterweight.
8. The reciprocating saw of claim 1 , wherein as the counterweight moves through a rearward half of the path, the counterweight generally moves in an upward direction, and as the counterweight moves through a forward half of the path, the counterweight generally moves in a downward direction.
9. The reciprocating saw of claim 1 , wherein the housing includes a battery support portion and a handle, wherein the handle supports a trigger, and wherein the battery support portion and the trigger are located on opposite sides of the motor axis.
10. A reciprocating saw comprising:
a housing including a battery support portion;
a motor positioned within the housing, the motor including a pinion rotatable about a motor axis; and
a drive mechanism positioned within the housing and coupled to the motor, the drive mechanism including:
a driven gear that engages the pinion and is rotated by the motor, the motor axis extending through a center of the driven gear to divide the driven gear into an upper portion and a lower portion,
an output shaft driven by the motor to reciprocate relative to the housing through a cutting stroke and a return stroke, the output shaft being located on a same side of the motor axis as the upper portion of the driven gear and configured to support a tool element, and
a counterweight coupled to the driven gear and rotating with the driven gear through a path and in a same rotational direction, the counterweight moving in an upward direction during a start of the cutting stroke of the output shaft, and moving in a downward direction during a start of the return stroke of the output shaft,
wherein the battery support portion is positioned on a same side of the motor axis as the lower portion of the driven gear.
11. The reciprocating saw of claim 10 , wherein the driven gear is rotated by the motor in the rotational direction about a central axis that is perpendicular to the motor axis.
12. The reciprocating saw of claim 11 , wherein the output shaft reciprocates along a spindle axis, wherein the motor axis and the spindle axis define a plane, and wherein the driven gear rotates about the central axis perpendicular to the plane.
13. The reciprocating saw of claim 12 , wherein the central axis intersects the motor axis.
14. The reciprocating saw of claim 12 , wherein the spindle axis is generally parallel to the motor axis.
15. The reciprocating saw of claim 10 , wherein the mass portion includes a leading edge, a trailing edge opposite the leading edge, and an aperture positioned closer to the trailing edge than to the leading edge in the rotational direction.
16. The reciprocating saw of claim 10 , wherein the pinion is positioned between the driven gear and the counterweight.
17. The reciprocating saw of claim 10 , wherein as the counterweight moves through a rearward half of the path, the counterweight generally moves in the upward direction, and as the counterweight moves through a forward half of the path, the counterweight generally moves in the downward direction.
18. A reciprocating saw comprising:
a housing;
a motor positioned within the housing, the motor including a pinion rotatable about a motor axis; and
a drive mechanism positioned within the housing and coupled to the motor, the drive mechanism including:
a driven gear that engages the pinion and is rotated by the motor, the driven gear having a circumference and being vertically-oriented within the housing with the motor axis extending through a center of the driven gear,
a connecting rod coupled to the driven gear to translate rotary motion of the driven gear into reciprocating motion,
an output shaft coupled to the connecting rod to reciprocate relative to the housing through a cutting stroke and a return stroke, the output shaft configured to support a tool element, and
a counterweight coupled to the driven gear and rotating with the driven gear through a path and in a same rotational direction, the counterweight moving in an upward direction during a start of the cutting stroke of the output shaft, and moving in a downward direction during a start of the return stroke of the output shaft, the counterweight including a connection portion coupled to the connecting rod and a mass portion including a leading edge, a trailing edge, and a curved outer perimeter matching the circumference of the driven gear, the curved outer perimeter extending more than 90 degrees between the leading and trailing edges.
19. The reciprocating saw of claim 18 , wherein the mass portion includes an aperture positioned closer to the trailing edge than to the leading edge in the rotational direction.
20. The reciprocating saw of claim 18 , wherein the output shaft reciprocates along a spindle axis, wherein the motor axis and the spindle axis define a plane, and wherein the driven gear rotates about the central axis perpendicular to the plane.