Abstract:
A handheld jigsaw, such as a compass saw ( 10 ), is disclosed that comprises a housing ( 12, 13 ) and a lifting rod ( 20 ) having a pendulum mechanism ( 38 ). The pendulum mechanism includes a pendulum lever ( 40 ) with which a pendulum stroke can be given during sawing to a saw blade ( 28 ) carried by the lifting rod ( 20 ). The lifting rod ( 20 ) is arranged such that it can rotate about its own axis ( 21 ) thereof and pivot transversely to the axis ( 21 ), and wherein the pendulum mechanism ( 38 ) can rotate about the axis ( 21 ).

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a 35 USC 371 application of PCT/EP 2009/055025 filed on Apr. 27, 2009. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is based on a hand-held power jigsaw. 
     2. Description of the Prior Art 
     Scrolling power jigsaws that are equipped with a saw blade that can pivot around its longitudinal axis are known, with which it is more convenient to saw curves than with conventional jigsaws because it is possible to orient the saw blade together with the lifting rod relative to the power jigsaw, tangentially to the curve to be sawn, without needing to turn the whole jigsaw. 
     Virtually all known high-quality jigsaws operate with an adjustable pendulum action in which during sawing, the saw blade—in addition to the axial up and down motion—is driven to oscillate transversely to the longitudinal axis in the plane of the advancing direction. This improves cutting performance. The pendulum action is transmitted directly to the saw blade spine usually by means of a pendulum lever equipped with a saw blade guide roller. The saw blade guide roller encompasses the saw blade spine in a form-locked, rolling fashion. It assures that the saw blade is always oriented straight ahead and prevents this saw blade position from changing. Therefore in known scrolling jigsaws, the pendulum action is deactivated in the scrolling mode and cannot be activated because in this mode, the saw blade leaves its straight-ahead position and is only able to do so when disengaged from the pendulum lever and/or pendulum roller. Due to the lack of pendulum action, the known jigsaws have a reduced cutting performance in scrolling mode. 
     ADVANTAGES AND SUMMARY OF THE INVENTION 
     The invention has the advantage that jigsaws, even in the scrolling mode, operate with pendulum action and therefore sawing progress is increased. This is achieved by the fact that during active pendulum action, the lifting rod can be rotated manually or in a motor-driven fashion. In addition, ergonomics and work safety are improved since lower operating forces and lower advancing force are required in the scrolling mode. 
     The pendulum action and scrolling mode can be combined with each other because the lifting rod is able to pivot around its own axis and also transversely to the axis, with the pendulum mechanism being able to rotate together with the lifting rod around its longitudinal axis. 
     The scrolling mode is secured in a simple way in that the pendulum mechanism has a pendulum lever and a support that holds the pendulum lever so that it is able to move, in particular around a pendulum axle, which support is coupled to the lifting rod in a rotary-driving fashion and the fact that the lifting rod is supported in a way that permits it to slide in relation to the support. 
     The scrolling mode is secured over a wide angular range in that pendulum lever is provided with means that ensure the transmission of a pendulum action to the saw blade in each of the possible rotary positions of the pendulum lever. 
     The scrolling mode is secured through a support surface that is provided on the pendulum lever and is oriented toward a pendulum action-transmitting element in a way that permits the stroke to be exerted on it across the rotation range of the pendulum lever. 
     The invention is simplified in that the support surface is embodied as annular, in particular in the form of a circular ring-shaped disc that is rigidly connected to the pendulum lever/roller lever. 
     This is characterized in that the support is supported in an axially fixed, rotatable fashion, particularly in the housing. 
     The scrolling mode is adjustable in that it is possible to adjust the support in rotary fashion from the outside by means of a transmission. 
     A simple adjusting mechanism for the scrolling mode is produced in that the support encompasses the lifting rod in annular fashion and is equipped with a gearing that can be coupled to an adjusting pinion that can be rotary driven by motor, by hand, or by means of an actuating mechanism. 
     The adjusting force for varying the scrolling mode can be introduced in a reliable way in that the actuating mechanism of the adjusting pinion has a rotary drivable actuating shaft. 
     The scrolling mode can be varied with simple means in that it is possible to adjust the actuating shaft in rotary fashion by hand, with control of the rotation angle. 
     The scrolling adjustment is easy to control because it is possible for the actuating shaft to be coupled to a manual rotation lever, rotary knob, or the like, which is provided with an indicator that can be adjusted relative to an angular scale. 
     The angular position of the saw blade can be adjusted and corrected in an automatic, particularly precise, and rapid fashion in that it is possible to adjust the actuating shaft in a rotary, sensor-controlled fashion by means of an actuating motor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be explained in greater detail below in conjunction with an exemplary embodiment with accompanying drawings. 
         FIG. 1  shows a side view of the hand-held power tool according to the invention, 
         FIG. 2  is a three-dimensional depiction of the lifting rod with the lifting drive and pendulum drive, 
         FIG. 3  is a front view of  FIG. 2 , 
         FIG. 4  is a side view of  FIG. 2 , 
         FIG. 5  is a top view of  FIG. 2 , 
         FIG. 6  is an enlarged three-dimensional view of  FIG. 2 , and 
         FIG. 7  shows a three-dimensional detail of the support. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The side view in  FIG. 1  shows a hand-held power tool according to the invention, embodied in the form of a jigsaw  10 , its motor housing  12  and transmission housing  13 , and its saw blade  28 , which protrudes downward through the opening  25  at the front of a base plate  11  and is secured in a clamping device  26  on a lifting rod  20 . In addition, the jigsaw  10  has a switch actuation lever  15  for switching its motor on and off and a power cord  19  for supplying power to the motor. The longitudinal axis  23  of the jigsaw  10 , which defines the normal advancing direction when sawing, extends parallel to the motor housing  12 . 
     In a transmission housing  13  schematically depicted in  FIG. 2 , the three-dimensionally depicted lifting rod  20  is supported with a lifting drive and pendulum drive. The drawing here shows a longitudinal guide  14  for a compensating weight  34  that is able to move in opposition to the lifting rod  20  and compensate for its oscillations and is supported so that it is able to move up and down on the rear side of a plate-like part of the transmission housing  13 . On its underside, the compensating weight  34  supports a pendulum action-transmitting element  36  in the form of a cam that transmits the up-and-down motion of the compensating weight  34  to a pendulum mechanism  38 , and in particular to a support surface  44  of a pendulum lever  40 , thus forcing the latter to execute a pendulum motion around its pendulum axle  41 . The support surface  44  is embodied in the form of an annular segment. The pendulum action-transmitting element  36  can therefore act on the support surface  44 , thus producing the pendulum action even in rotated positions of the pendulum lever  40  around the lifting rod axis  21 . The pendulum lever  40  can only be pivoted together with the support  46  around the lifting rod axis  21 , away from the straight-ahead position of the saw blade  28 . 
     The pendulum axle  41  of the pendulum lever  40  is situated on a support  46 , whose lower region  48  extends behind the saw blade and flush with it and whose upper region  50  encompasses the lifting rod  20  in annular fashion. With its rotatable guide roller  42  at the lower end, the pendulum lever  40  rests against the spine of the saw blade  28 . In so doing, it embraces the spine of the saw blade  28  laterally, permitting its rolling motion. The upper region  50  of the support  46  is supported in the transmission housing  13  so that it is axially immobile, but able to rotate around the lifting rod axis  21 . 
     With a central square hole  51  ( FIGS. 6 and 7 ), the support  46  encompasses the cross-sectionally rectangular or square lifting rod  20  so that the latter is easily able to execute its vertical stroke motion and its forward and back pendulum action. If the support  46  is rotated around the lifting rod axis  21  in an axial bearing  52  ( FIG. 4 ), the pendulum lever  40  and lifting rod  20  follow along. For this purpose, the square hole  51  is dimensioned so that it has only a small amount of play transversely to the lifting rod  20 , but has considerably more play in the direction of the pendulum action than in the transverse direction, as required by the lifting rod  20  for the pendulum action. 
     The lifting rod  20  has a sliding block  18  at the top ( FIG. 2 ). By means of this sliding block, the lifting rod  20  is driven in longitudinally reciprocating fashion. The sliding block  18  is guided so that it can slide up and down in a longitudinal guide  16  affixed to the housing, in front of the front side of the plate-like part of the transmission housing  13 . An eccentric pin  32  of an eccentric gear  30  situated between the plate-like part and the lifting rod extends through the sliding block in a transversely extending sliding block slot  17 . The eccentric pin  32  drives the sliding block  18  and together with it, the lifting rod  20 . By means of an axle oriented toward the rear, the eccentric gear  30  is supported in rotary fashion on the plate-like part of the transmission housing  13 . 
     To enable the lifting rod  20  to rotate around the lifting rod axis  21 , it is supported in rotary fashion on a sliding block  18  with a swivel  22  that defines the lifting rod axis  21 . Below the swivel  22 , the lifting rod  20  has a pendulum linkage  24  that permits the pendulum motion of the lifting rod  20  and saw blade  28  together with the clamping device  26 . 
     In its upper region  50  embodied in the form of a live ring, the support  46  is provided with an internal gearing  54  that is engaged by a planetary wheel-like adjusting pinion  56 , which is able to rotate by means of an actuating shaft  58  oriented vertically upward. Through a rotary actuation of the actuating shaft  58 , it is possible to rotationally adjust the support  46  and together with it, the pendulum lever  40 , guide roller  42 , and lifting rod  20 . It is thus possible within certain limits to saw and scroll when the jigsaw  10  is in scrolling mode, i.e. provided that it is possible for the pendulum action-transmitting element  36  to contact the support surface  44  in a supporting fashion. If the support surface is embodied in the form of a 180° ring segment, then it is possible to scroll across this angular range. 
       FIG. 3  is a schematic depiction of the transmission housing  13  from  FIG. 2 , in a front view that shows the details in  FIG. 2  from a different viewing angle, in particular the plate-like part of the transmission housing  13  and the embodiment of the eccentric gear  30 ; details that have already been explained in conjunction with  FIG. 2  need not be described again here. 
       FIG. 4  is a schematically depicted side view of the transmission housing  13  from  FIG. 2 ; in addition to the depiction in  FIG. 3 , in this case the axial bearing  52  for the upper region  50  of the support  46  embodied as a live ring, is depicted. Here, too, it is not necessary to describe details that have already been explained in conjunction with  FIG. 2 . 
       FIG. 5  is a schematically depicted top view of the transmission housing  13  from  FIG. 2 ; in addition to the depiction in  FIG. 3 , in this case the live ring  50  of the support  46 , with its gearing  54  and the adjusting pinion  56 , is particularly visible. Here, too, it is not necessary to describe details that have already been explained in conjunction with  FIG. 2 . 
       FIG. 6  shows another enlarged three-dimensional depiction that is essentially the same as the one in  FIG. 2 ; it is not necessary to repeat the description of details already explained in conjunction therewith. 
       FIG. 7  is a three-dimensional view of the support  46  as a separate part, clearly depicting the lower region  48  and upper region  50 , the gearing  54 , the oblong-dimensioned square hole  51 , and the bores  39 . 
     Through rotation of the actuating shaft around its axis, the support rotates around its axis together with its live ring and consequently also the roller lever and lifting rod. This changes the angular position of the saw blade and assures the pendulum function (synchronous to the saw blade). 
     In this case, the lifting rod rotation can be controlled in an autonomous or remote-controlled fashion by means of an optoelectronic unit. 
     The foregoing relates to the preferred exemplary embodiment of the invention, it being understood that other variants and embodiments thereof are possible within the spirit and scope of the invention, the latter being defined by the appended claims.