Mode selection mechanism for power tool, and power tool incorporating such mechanism

Abstract

A mode selection apparatus for a jigsaw having scrolling and orbital modes is disclosed. The mode selection apparatus comprises a locking arm ( 76 ) moveable between a first position in which a scroller knob ( 56 ) is rotatable relative to the tool housing, a second position in which the locking arm engages the scroller knob to prevent it from rotating relative to the tool housing and an output shaft of the jigsaw is prevented from pivoting about a pivot axis transverse to the longitudinal axis of the output shaft, and a third position in which the scroller knob is prevented from rotating relative to the tool housing and the output shaft is causes to pivot about the pivot axis. The locking arm ( 76 ) has a slot ( 84 ) for engaging a tooth ( 86 ) on a scroll selector ( 48 ) for moving the locking arm between the first, second and third positions thereof. The tooth ( 86 ) remains in engagement with the slot ( 84 ) during movement of the locking arm between the first, second and third positions.

1 . A mode selection apparatus for a power tool having a tool housing, a motor arranged in the tool housing, and an output shaft adapted to be driven in a reciprocating motion relative to the tool housing by means of the motor and to support a working member of the tool for reciprocating motion of the working member relative to the tool housing, the mode selection apparatus comprising: 
 at least one locking member moveable between a respective first position in which said output shaft of the tool is pivotable about its longitudinal axis, a respective second position in which the output shaft is prevented from pivoting about its longitudinal axis and is prevented from engaging a drive mechanism to prevent the output shaft from pivoting about a pivot axis transverse to said longitudinal axis, and a respective third position in which the output shaft is prevented from pivoting about its longitudinal axis and engages said drive mechanism to cause the output shaft to pivot about the pivot axis transverse to said longitudinal axis, wherein said locking member has at least one respective recess; and    at least one mode selection member for engaging said locking member for moving the locking member between first, second and third positions thereof and having at least one protrusion for engaging said recess on said locking member;    wherein at least one said protrusion of said mode selection member is adapted to remain in engagement with the corresponding said recess of said locking member during movement of said locking member between said first, second and third positions thereof.    
   
   
       2 . An apparatus according to  claim 1 , wherein at least one said locking member is adapted to engage a first actuator member on said tool housing in said second and third positions to prevent rotation of said first actuator member relative to the tool housing.  
   
   
       3 . An apparatus according to  claim 2 , wherein at least one said locking member is adapted to engage at least one respective slot on the first actuator member.  
   
   
       4 . An apparatus according to  claim 1 , wherein at least one said mode selection member has at least one respective cam surface for causing the output shaft to move out of engagement with the drive mechanism to prevent the output shaft from pivoting about the pivot axis transverse to said longitudinal axis.  
   
   
       5 . An apparatus according to  claim 4 , wherein at least said one cam surface is a groove.  
   
   
       6 . An apparatus according to  claim 5 , wherein at least one said cam surface is a protrusion.  
   
   
       7 . An apparatus according to  claim 1 , wherein at least one said mode selection member is adapted to rotate relative to the tool housing.  
   
   
       8 . An apparatus according to  claim 1 , further comprising at least one first actuator member for enabling rotation of the output shaft about said longitudinal axis.  
   
   
       9 . An apparatus according to  claim 8 , further comprising at least one second actuator member for actuating at least one said mode selection member for moving at least one said locking member between first, second and third positions thereof.  
   
   
       10 . An apparatus according to  claim 1 , said power tool comprising a jigsaw.  
   
   
       11 . A jigsaw comprising: 
 a housing;    a motor;    an output shaft driven in reciprocating motion relative to the tool housing by said motor and supporting a working member, said output shaft disposed for both rotational motion about a longitudinal axis thereof and pivoting motion about an axis transverse to said longitudinal axis;    a cam face and a cam follower operatively disposed between said motor and said output shaft and selectively disposed so as to cooperate to drive said output shaft in said pivoting motion;    a locking arm movable in the direction of said longitudinal axis between a first position in which said output shaft is rotable about its longitudinal axis and said cam face and said cam follower are displaced from each other such that said output shaft is not driven in pivoting motion, a second position in which the output shaft is prevented from rotating about its longitudinal axis and said cam face and said cam follower are displaced from each other such that said output shaft is not driven in pivoting motion, and a third position in which the output shaft is prevented from rotating about its longitudinal axis and said cam face and said cam follower cooperate to drive said output shaft in pivoting motion.