US20120000080A1 - Hand-held power jigsaw - Google Patents

Abstract

A hand-held jigsaw includes a saw blade and control element for automating a tracking the saw blade, the hand-held jigsaw, or both along layout lines. A sensor, preferably a camera unit, detects a layout line provided on a work piece.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• The present invention is a divisional application of co-pending U.S. application Ser. No. 12/281,442, filed Sep. 2, 2008. The invention described and claimed hereinbelow is also described in GermanPatent Application DE 10 2006 052 608.5 filed on Nov. 9, 2006. These German Patent Applications, whose subject matter is incorporated here by reference, provides the basis for a claim of priority of invention under 35 U.S.C. 119(a)-(d).
BACKGROUND OF THE INVENTION
• The present invention is based on a hand-held jigsaw.
• For example, the publications US 2005/0060896 A1 and US 2005/0257985 A1 have disclosed jigsaws that are referred to as “scrolling jigsaws” and in which the saw blade is situated so that in addition to executing the stroke motion, it can be rotated manually independently of the sawing motion. This additional function facilitates the sawing of sinuous cuts.
• Without additional guidance-assisting elements, sawing precisely along a predetermined contour with a jigsaw requires a large amount of practice. This task is additionally complicated by the exertion of transverse forces that cause the saw blade to go astray. Providing laterally supporting assistance systems or various navigation aids (e.g. lasers) reduces these problems, but does not eliminated them.
SUMMARY OF THE INVENTION
• The invention is based on a hand-held jigsaw, in particular a scrolling jigsaw.
• According to the invention, control means are provided that make it possible to automate a tracking of a saw blade and/or of the hand-held jigsaw along layout lines. In this context, a “control means” is understood in particular to be a means that permits a required orientation of the saw blade and/or the hand-held jigsaw and/or a component of the hand-held jigsaw such as a glide element to be detected and/or adapted to the orientation. This control means can be a detection unit such as a sensor system embodied in the form of a sensor and/or an actuator system embodied in the form of an actuating unit such as a servo motor and/or a step motor and/or a piezoelectric actuator. Alternatively, it would also be conceivable to use a DC motor. The term “tracking” here defines an orientation along a predetermined path that is preferably indicated by means of a marking. This marking can be a layout line such as a previously drawn pencil line and/or another marking deemed suitable by a person skilled in the art, such as an indentation and/or some other form of profiling.
• The system is used to assist an operator and therefore to facilitate the sawing procedure. Taking advantage of the existing degree of freedom of the saw blade in the form of the already implemented rotation axis, the hand-held jigsaw is equipped with a special sensor system for detecting a previously drawn line or layout line and a corresponding actuator system for automatically adjusting the saw blade angle from an angle range of a pivot angle. The rotation axis here is defined by a normal that extends through a center point of a plane defined by a thickness and a width of the saw blade. Alternatively, the rotation axis of the saw blade can also be situated other than at its center point. In this case, the pivot angle represents the angle by which the saw blade can be maximally adjusted around its longitudinal axis in relation to a longitudinal axis of the glide element and/or another guidance component deemed suitable by a person skilled in the art, e.g. a chassis. This pivot angle is preferably an angle of between 0° and 90°. By contrast, the saw blade angle of the saw blade is the angle that is actually set between the lateral span of the saw blade and the longitudinal axis of the glide element or a guidance component. By means of a saw blade motion that is overlaid with a hand-guided movement of the operator, it is possible to more precisely track a previously drawn contour. Straight cuts can also be implemented without additional guides.
• This produces a significantly improved work result while simultaneously simplifying operation.
• It is also advantageous if it is possible to switch off means that are provided for automating a tracking of the saw blade and/or the hand-held jigsaw along layout lines. This makes it possible to create a hand-held jigsaw that can be used in a particularly flexible fashion.
• If a hand-held jigsaw has a pivotable saw blade that can be driven by the control means, then a tracking of the previously drawn line by the saw blade can occur in an advantageous, structurally simple fashion. The term “pivotable” here is particularly understood to mean a turning and/or rotation of the saw blade in an axis that preferably extends parallel to a longitudinal span of the saw blade. In this connection, the turning can be achieved by clamping the saw blade into a tool socket and/or through some other exertion of force on the saw blade.
• The invention is also based on a hand-held jigsaw, in particular a scrolling jigsaw.
• According to the invention, a sensor is provided for detecting a layout line provided on a workpiece. The term “sensor” is understood in particular here to mean a camera unit and/or a contrast sensor unit and/or an eddy current sensor unit. This makes it possible to achieve a detection of a desired cutting direction in a particularly advantageous, inexpensive, structurally simple fashion.
• Also according to the invention, optical mouse sensors are provided for determining a speed and/or a movement direction. The term “optical mouse sensor” is understood here to mean a sensor that uses optical means such as a light-emitting diode or laser diode to illuminate a supporting surface, evaluates a light reflected against the supporting surface, calculates a speed based on the change of a physical surface of the supporting surface, and from this, calculates the movement data in the x and/or y direction. Alternatively, the movement direction and/or the advancing speed can also be determined by means of a running wheel with an angular displacement transducer, e.g. a rolling element with corresponding photoelectric beam, detectors that detect a movement in at least two directions such as an x direction and a y direction. In addition, means that are used to compare individual camera images can also be provided to determine the advancing speed. The use of optical mouse sensors makes it possible for a rugged sensor system for determining the speed and/or a movement direction to be produced in a particularly simple and inexpensive fashion.
• It is also advantageous if an actuator with a regulator is provided. An “actuator with a regulator” is understood here to be a unit that processes data from a detection unit, particularly in a control loop, and/or reacts to and/or transmits generated control signals. This unit is preferably embodied in the form of a servo motor and/or a step motor and/or a piezoelectric actuator and/or a DC motor with a regulator unit. It is thus possible for a control loop for precisely tracking a predetermined cutting line to be implemented in a structurally simple and inexpensive fashion.
• According to the invention, a display element is produced, which is provided to display a recommended advancing direction. A “display element” is understood here to mean an element that optically, acoustically, and/or tactilely informs the operator of the path detected by a sensor or of a course of the layout line. The display element here can be composed of LEDs and/or a display and/or another data unit deemed suitable by a person skilled in the art. This makes it advantageously possible for an operator to receive information relating to a desired movement direction, regardless of whether the operator is able to see the saw blade. This makes it possible for an operator to stay within an optimal working region that represents an angular range of the possible saw blade angle.
BRIEF DESCRIPTION OF THE DRAWINGS
• Other advantages ensue from the following description of the drawings. An exemplary embodiment of the invention will be explained in greater detail in conjunction with the associated drawings. The drawings, the description, and the claims contain numerous defining characteristics in combination. Those skilled in the art will also suitably consider the defining characteristics individually and unite them into other meaningful combinations.
• FIG. 1 shows a hand-held jigsaw according to the invention,
• FIG. 2 shows a glide shoe of the hand-held jigsaw according to the invention, embodied in the form of a base plate and equipped with optical sensors,
• FIG. 3 shows an alternative glide shoe of the hand-held jigsaw according to the invention, embodied in the form of a base plate,
• FIG. 4 shows an alternative glide shoe of the hand-held jigsaw according to the invention, embodied in the form of a base plate and equipped with alternative sensors, and
• FIG. 5 shows a top view of the hand-held jigsaw.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
• FIG. 1 is a perspective side view of a hand-heldjigsaw9 according to the invention, embodied in the form of a scrolling jigsaw. The hand-heldjigsaw9 includes amachine housing44, amain handle46 integrated into themachine housing44, and atool socket48 containing a tool in the form of a rotatably supported sawblade12. A glide element or glide shoe8 in the form of a base plate is situated on aside50 oriented toward thework piece18 to be machined. This glide shoe8 permits the hand-heldjigsaw9 to advantageously glide on thework piece18. On theside52 oriented away from thesaw blade12, in a region that can be associated with themain handle46, a guide knob is provided, which is used for an at least manual guidance of the hand-heldjigsaw9. Themachine housing44 also contains a motor that is not shown in detail. On themain handle46, anactuation switch56 is provided, which can be used to switch the hand-heldjigsaw9 on and off. In aside region58 of themachine housing44, an adjustingswitch60 is also provided, which can be used to adjust the glide shoe8 in relation to amain span62 of thesaw blade12.
• The hand-heldjigsaw9 includes control means10,100 that enable an automation of a tracking of thesaw blade12 along thelayout line14. The control means10 is situated in apart66 of themachine housing44 spaced apart from themain handle46 in theaxial direction64. The control means10 includes asensor16 for detecting or optically scanning a marking orlayout line14 in the form of a normal pencil line3 provided on thework piece18. Thesensor16 is composed of a camera unit7 that preferably includes a low-cost camera and that is associated with aprocessor unit28. In principle, thesensor16 could also be acontrast sensor unit20 and/or eddycurrent sensor unit22 associated with arespective processor unit28. For an optimal detection of the previously drawnline14, it would also be conceivable for theeddy current sensor22 to be situated in the glide shoe8.
• Amonitoring region68 of thesensor16 and of the camera unit7 extends toward thework piece18 in the same direction as themain span62 of thesaw blade12 and covers a 360° angular range around thesaw blade12. Themonitoring region68 of the camera unit7 represents the region in which thesaw blade12 functions in an operating mode, preferably a sawing procedure of awork piece18. Around thesaw blade12, the glide shoe8 has asemicircular opening70 in which thesaw blade12 is centrally situated. In the direction of an advancingdirection38 and in the direction of themonitoring region68, theopening70 has arectangular viewing window102. The glide shoe8 also has areference mark74 that represents the intersecting point of anedge76 of the glide shoe8 with alongitudinal axis78 of the glide shoe8 (seeFIG. 2).
• FIG. 3 shows an alternative embodiment of the glide shoe8. In this case, thecentral opening70 widens out in a V-shape to form aviewing region72.
• FIG. 4 shows another alternative embodiment of the glide shoe8 with acircular opening70. In this case, the glide shoe8 is closed in themonitoring region68 and is embodied as transparent, e.g. is composed of Plexiglas, in order to make it possible to monitor thelayout line14 on the work piece18 (seeFIG. 4).
• In addition, themachine housing44 of thehandheld jigsaw9 contains acompact actuator system2 that is able to adjust thesaw blade12 around a rotation axis1 in an automated fashion. The control means100 is provided for this purpose. For the tracking of the rotatable sawblade12, the saw blade is driven in rotary fashion by the control means100. The control means100 represents anactuator unit30, embodied in the form of an actuator with aregulator34 in the form of a step motor by means of which it is possible to adjust asaw blade angle26 of asaw blade12. The control means100 and the step motor can also be situated in a space-saving fashion as an alternative to theguide knob54. In this case, thesaw blade angle26 is an angle □ from the angular range of apivot angle80 that is actually set between thewidth span82 of thesaw blade12 and thelongitudinal axis78 of the glide shoe8. Thepivot angle80 represents the angle □_maxby which thesaw blade12 can be moved around its longitudinal axis, which extends parallel to themain span direction62 of thesaw blade12, in relation to alongitudinal axis78 of the glide shoe8 (seeFIG. 2).
• With the aid of the control means10,100, namely thesensor16 and theactuator unit30, it is possible to implement a control loop in order to achieve the most exact possible tracking of the predetermined line orlayout line14. The exceptional feature in this case lies on the one hand in the fact that an analog image processing is used to detect thelayout line14 and on the other hand, lies in the automation of the system. It is consequently possible to execute clean, precise cuts by hand and to actively prevent a deviation of thesaw blade12.
• An operating sequence will be described in greater detail below.
• Thesensor16 in the form of a camera unit7 detectsindividual points4 of the previously drawn line orlayout line14. In this case, in order to detect thelayout line14, thesensor16 uses an analog image processing that uses a division of themonitoring region68 into individual search lines6 without digital image processing. In the analog image processing, the use of the camera unit7 is particularly advantageous since it does not require calculation-intensive digital image processing.
• The collected sensor information and the data associated with the detectedpoints4 are then transmitted by thesensor16 to theprocessor unit28, which processes the detectedpoints4 further and based on them, interpolates and adapts an actual path curve24 (spline). Theprocessor unit28 can be a microcontroller or another processing unit deemed suitable by a person skilled in the art.
• Theprocessing unit28 calculates and generates control signals and transmits control signals to theactuator unit30 for an adjustment of thesaw blade angle26. By means of an actuating element with aregulator34 in the form of a step motor, theactuator unit30 then correspondingly adapts thesaw blade angle26, i.e. the angle □ around the longitudinal axis parallel to themain span direction62 of thesaw blade12, as a function of the overlaid user guidance by means of theguide knob54 of the hand-heldjigsaw9.
• At the same time, the use of thesensor16 and the camera unit7 also offers the possibility of measuring additional reference marks74 by means of the glide shoe8. Furthermore, thesensor16 can be used for detecting the set sawblade angle26 and for determining the rotation angle of thesaw blade12. This makes it possible to eliminate additional cost-intensive sensors that unnecessarily take up space.
• An additional, alternative embodiment is the integration of a detection of an advancing speed. To this end,optical mouse sensors5 are situated in the glide shoe8 on aside84 oriented toward thework piece18 and determine the speed and a movement direction, preferably in the x and/or y direction (seeFIG. 3).
• FIG. 4 shows another possibility for detecting the advancing speed. In this case, a simple running wheel with anangular displacement transducer32 is provided, e.g. a rollingelement86 with correspondingphotoelectric beam detectors88. In principle, other approaches are also conceivable, for example the comparison of individual camera images by means of theprocessor unit28. Within certain limits, the system can also be implemented without a speed measurement.
• When the hand-heldjigsaw9 is used, i.e. during a sawing process, an operator guides the hand-heldjigsaw9 manually by means of themain handle46 and guideknob54; the operator must roughly predetermine the cutting direction. The system composed of the control means10,100, i.e. of thesensor16 andactuator unit30, is conceived only for the fine regulation that compensates for irregularities in the saw blade path and/or user guidance.
• This system is understood solely as an assisting system, i.e. if nolayout line14 can be detected (end of a line, multiple lines), the system gives a warning by means of an acoustic and/oroptical unit90, stabilizes the currentsaw blade angle26, and leaves the control up to the operator, as in conventional jigsaws. No active intervention occurs. If so desired, the system, which can be associated with one or more means and which permits automation of a tracking of thesaw blade12 and/or the hand-heldjigsaw9 alonglayout lines14, can be switched off at any time, even preferably manually by the operator. The system advantageously includes theactuator system2, at least one or speed-detecting sensor such as theoptical mouse sensor5, the control means10 in the form of thesensor16 and the camera unit7, the control means100 in the form of theactuating unit30, and the actuator with aregulator34. For the switching off, aswitch92 is provided in the region of themain handle46 on themachine housing40.
• As shown inFIG. 4, adisplay element36, e.g. in the form ofLEDs40 and/or adisplay42, is situated on aside94 of themachine housing44 ormain handle46 oriented toward the operator, in the operator's field of view. Thisdisplay element36 is provided to display a recommended advancingdirection38, for example symbolized by means of anarrow symbol96 composed of light-emitting diodes orLEDs40. The operator is thus shown the direction in which the saw movement must be corrected. Consequently, thedisplay element36 makes it possible for the operator to stay within an optimum working region that represents an angular range of the possiblesaw blade angle26.
• In another embodiment of the invention, in order to improve visibility, ablower98 is provided, which is able to remove or suck away machining residue generated by the sawing process.
• On the whole, this makes it possible to significantly simplify the guidance of the hand-heldjigsaw9 while achieving a simultaneously improved sawing result. Another advantage of this system lies in the fact that the often poor visibility of the sawing location now plays only a subordinate role since the fine guidance is performed by the system anyway.

Claims (17)

1. A hand-held jigsaw, comprising:

a saw blade;

control means for automating a tracking of an element selected from the group consisting of a saw blade, the hand-held jigsaw, and both along layout lines; and

a sensor for detecting a layout line provided on a work piece, wherein the sensor is configured to detect individual points of a previously drawn line.

2. The hand-held jigsaw as recited inclaim 1, wherein the sensor is a sensor selected from the group consisting of a contrast sensor unit, an eddy current sensor unit and both.

3. The hand-held jigsaw as recited inclaim 2, wherein the contrast sensor unit or the eddy current sensor unit is configured to interpolate an actual path curve based on the detected points.

4. The hand-held jigsaw as recited inclaim 3, wherein the contrast sensor unit or the eddy current sensor is configured to adopt a saw blade angle as a function of an overlaid user guidance of the hand-held jigsaw.

5. A hand-held jigsaw, comprising:

a saw blade;

control means for automating a tracking of an element selected from the group consisting of a saw blade, the hand-held jigsaw, and both along layout lines; and

a sensor for detecting a layout line provided on a work piece, wherein the sensor is a sensor selected from the group consisting of a contrast sensor unit, an eddy current sensor unit and both.

6. The hand-held jigsaw as recited inclaim 5, further comprising a processor unit that is configured to perform a process selected from the group consisting of generating control signals, transmitting control signals, and both to an actuator unit for an adjustment of a saw blade angle.

7. The hand-held jigsaw as recited inclaim 6, wherein the actuator unit adapts the saw blade angle as a function of an overlaid user guidance of a hand-held jigsaw.

8. The hand-held jigsaw as recited inclaim 6, wherein the actuator unit is a mechanical/actuator system for adjusting the saw blade angle of a saw blade.

9. The hand-held jigsaw as recited inclaim 5, further comprising optical mouse sensors for determining a speed and a movement direction.

10. The hand-held jigsaw as recited inclaim 5, further comprising means for comparing individual camera images to determine an advancing speed.

11. The hand-held jigsaw as recited inclaim 5, further comprising an actuator with a regulator.

12. The hand-held jigsaw as recited inclaim 11, wherein the actuator with the regulator is a unit selected from the group consisting of a servo motor, a step motor, and a piezoelectric actuator, and any combination thereof.

13. The hand-held jigsaw as recited inclaim 1, wherein means that permit an automation of the element is switchable.

14. The hand-held jigsaw as recited inclaim 1, further comprising a display element provided to display a recommended advancing direction.

15. The hand-held jigsaw as recited inclaim 14, wherein the display element is selected from the group consisting of LEDs, a display, and both.

16. The hand-held jigsaw at least as recited inclaim 1, wherein the saw blade is pivotable and drivable by the control means.

17. The hand-held jigsaw as recited inclaim 1 or5, wherein the hand-held jigsaw is a scrolling jigsaw.

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