Abstract:
A method for controlling a device system ( 10 ) during the cutting of a workpiece ( 18 ) along a cutting line ( 43 ) up to a first end point (E 1 ) using a saw head ( 12 ) that can be moved on a guide rail ( 11 ) along an advancing direction ( 26 ), whereby the saw head ( 12 ) is arranged on the guide rail ( 11 ) in a starting position (X 0 ), and a first partial length (L 1 ) extending from the starting position (X 0 ) to the first end point (E 1 ) of the cutting line ( 43 ) is entered.

Description:
[0001]    The present invention to method for controlling a device system during the cutting of a workpiece along a cutting line. 
       BACKGROUND  
       [0002]    In manual processes for cutting a workpiece along a cutting line, the operator has to approach the end points of the cutting line by manually controlling the motor-driven advancing mechanism during the processing. If the saw blade is surrounded by a blade guard, the exit points of the saw blade in the workpiece are hardly or not at all visible to the operator, so that the operator cannot determine the end points of a cutting line during the work process. 
         [0003]    European patent application EP 1 693 173 A1 discloses a method that is at least partially automated for controlling a device system during the cutting of a workpiece along a cutting line. The device system consists of a guide rail, a saw head that is arranged so as to be movable on the guide rail and a motor-driven advancing mechanism to move the saw head along the guide rail. The saw head comprises a saw blade that is attached to a saw arm and that is driven around a rotational axis. The saw arm is configured so that it can be swiveled around a swivel axis. The cutting depth of the saw blade in the workpiece is varied by a swiveling movement of the saw arm around the swivel axis. The saw blade is rotated around the rotational axis by a drive motor, while the saw arm is swiveled by a swivel motor. The drive motor and the swivel motor are arranged in a device housing of the saw head. The motor-driven advancing mechanism comprises a guide carriage and an advancing motor that is arranged in the device housing. The saw head is installed on the guide carriage and configured so as to be movable by the advancing motor along the guide rail in an advancing direction. Aside from the motors, there is also a control unit that is installed in the device housing and that serves to control the wall saw and the motor-driven advancing mechanism. 
         [0004]    This prior-art method for controlling the device system during the cutting of a workpiece entails a sequence of three method steps that are carried out one after the other. In the first method step, the saw arm is slanted at a swivel angle that corresponds to the depth of the partial cut. In the second method step, the saw head is moved forward along the guide rail along the advancing direction until it reaches the first end point of the cutting line. In the third method step, the saw head is moved backwards along the guide rail along the advancing direction until it reaches the second end point of the cutting line. These three method steps are continuously repeated until the desired cutting depth has been reached. The at least partially automated cutting method requires the operator to enter the end points of the cutting line but it does not contain any information about how the coordinates of the end points are specified by the operator. 
       SUMMARY OF THE INVENTION  
       [0005]    It is an object of the present invention to provide a method for controlling a device system during the cutting of a workpiece along a cutting line in such a way that it becomes easier for the operator to determine the end points. 
         [0006]    The present invention provides that the saw head is arranged on the guide rail in a starting position and a first partial length extending from the starting position to the first end point of the cutting line is entered. The operator can arrange the saw head on the guide rail at any desired starting position between the first and second end points of the cutting line. The coordinates of the first end point are calculated in a control unit of the device system on the basis of the first partial length. In this context, the first partial length comprises not only the value but also the direction in which the first partial length is measured beginning at the starting position. 
         [0007]    A suitable starting position for a swiveling saw arm is, for example, the position of the swivel axis of the saw arm since, during the swiveling movement, the position of the swivel axis remains unchanged in the advancing direction. The starting position as well as a positive and a negative direction beginning at the starting position are indicated by a mark on the saw head. The operator measures the distance from the starting position to the first end point and then enters this value, together with the direction in which the first partial length is measured. 
         [0008]    In a preferred variant, the total length extending from the first end point to a second end point of the cutting line is entered. The positions of the end points of the cutting line are calculated in the control unit of the device system on the basis of the first partial length and the total length. Entering the total length is advantageous when the work task prescribes the total length of the cut. If the total length is known, only one partial length between the starting position of the saw head and one of the end points needs to be measured. The measuring effort is reduced in comparison to a work task which requires that both lengths be measured. 
         [0009]    In an alternative preferred variant, a second partial length extending from the starting position to a second end point of the cutting line is entered. In this context, the second partial length comprises not only the value but also the direction in which the second partial length is measured beginning at the starting position. The positions of the end points of the cutting line are calculated in the control unit of the device system on the basis of the first and second partial lengths (value and direction). Entering the second partial length is advantageous when the work task does not prescribe the total length of the cut and the measuring of the total length involves a greater effort. 
         [0010]    In a preferred embodiment, the operator enters the first partial length, the second partial length and/or the total length of the cutting line by means of a control unit. Entering the lengths manually has the advantage that any measuring device can be used by the operator in order to measure the distance. 
         [0011]    In an alternative preferred embodiment, the first partial length, the second partial length and/or the total length of the cutting line are entered by means of a sensor system. The use of a sensor system has the advantage that the measured lengths can be transmitted directly by the sensor system to the control unit of the device system, as a result of which the risk of erroneous transmission is reduced. 
         [0012]    Especially preferably, the first partial length, the second partial length and/or the total length of the cutting line are transmitted by the sensor system to the device system via a communication connection. The operator measures one or more of the lengths by means of the sensor system and establishes a communication connection between the sensor system and the control unit of the device system. Since the lengths are transmitted via a communication connection, the sensor system can be employed with several device systems. 
         [0013]    Embodiments of the invention will be described below with reference to the drawing. The drawing does not necessarily depict the embodiments true-to-scale, but rather, the drawing—where necessary for the sake of explanation—is shown in schematic and/or slightly distorted form. Regarding any additions to the teaching that can be gleaned directly from the drawing, reference is hereby made to the pertinent state of the art. Here, it should be kept in mind that many modifications and changes relating to the shape and to details of an embodiment can be made without departing from the general idea of the invention. The features of the invention disclosed in the description, in the drawing as well as in the claims can be essential for the refinement of the invention, either individually or in any desired combination. Moreover, all combinations of at least two of the features disclosed in the description, in the drawing and/or in the claims fall within the scope of the invention. The general idea of the invention is not limited to the exact form or detail of the preferred embodiment shown and described below nor is it limited to a subject matter that would be limited in comparison to the subject matter put forward in the claims. At given rated ranges, values that fall within the specified limits are also disclosed as limit values and can be used and claimed as desired. For the sake of clarity, identical or similar parts or else parts with an identical or similar function are designated by the same reference numerals below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0014]    The following is shown: 
           [0015]      FIG. 1 : a rail-guided device system consisting of a guide rail, a saw head that is arranged so as to be movable on the guide rail and a motor-driven advancing mechanism to move the saw head along the guide rail; 
           [0016]      FIG. 2 : the device system shown in  FIG. 1 , during the creation of a cut between a first and a second end point, without overcuts; and 
           [0017]      FIG. 3 : the device system of  FIG. 1 , during the creation of a cut between a first and a second end point, with overcuts. 
       
    
    
     DETAILED DESCRIPTION  
       [0018]      FIG. 1  is a schematic view of a rail-guided device system  10 , consisting of a guide rail  11 , a power tool  12  that is arranged so as to be movable on the guide rail  11 , and a motor-driven advancing mechanism  13  to move the power tool  12  along the guide rail  11 . 
         [0019]    The power tool is configured as a saw head  12  and it comprises a saw blade  14  that is attached to a saw arm  15  and that is driven around a rotational axis  16 . The saw arm  15  is configured so that it can be swiveled around the swivel axis  17 . The cutting depth of the saw blade  14  is varied by a swiveling movement of the saw arm  15  around the swivel axis  17 . The swivel angle of the saw arm  15 , together with the diameter of the saw blade  14 , determines how deep the saw blade  14  plunges into the workpiece  18  that is to be processed. As an alternative to the swiveling movement of the saw arm  15  around the swivel axis  17 , the saw arm  15  can be adjusted, for instance, by means of a linear drive or another such drive unit. In order to protect the operator, the saw blade  14  can be surrounded by a blade guard that is attached to the saw arm  15  by means of a blade guard holder. 
         [0020]    The saw blade  14  is rotated around the rotational axis  16  by a drive motor  21 , while the saw arm  15  is swiveled around the swivel axis  17  by a swivel motor  22 . The drive motor  21  and the swivel motor  22  are arranged in a device housing  23  of the saw head  12 . The motor-driven advancing mechanism  13  comprises a guide carriage  24  and an advancing motor  25  that is arranged in the device housing  23 . The saw head  12  is installed on the guide carriage  24  and configured so as to be movable by the advancing motor  25  along the guide rail  11  in an advancing direction  26 . The device housing  23  accommodates not only the motors  21 ,  22 ,  25 , but also a first control unit  27  to control the saw head  12  and the motor-driven advancing mechanism  13 . 
         [0021]    The device system  10  is operated by means of a control unit  28  which, in the embodiment shown in  FIG. 1 , is configured as a remote control unit. The remote control unit  28  comprises a device housing  29 , a second control unit  31  accommodated in the device housing  29  as well as an operating means  32  and a display means  33  that are arranged on the top  34  of the device housing  29 . The second control unit  31  is connected to the first control unit  27  via a communication connection  35 . The communication connection  35  is configured as a hard-wired connection or else as a wireless communication connection, for example, in the form of an infrared, Bluetooth, WLAN or Wi-Fi connection. Aside from the listed wireless connection technologies, all familiar and future wireless connection technologies for data transmission are suitable. 
         [0022]    The device system  10  has a sensor system  36  with several sensor elements in order to monitor the device system  10  and the work process. A first sensor element  37  is configured as a swivel-angle sensor, while a second sensor element  38  is configured as a position sensor. The swivel-angle sensor  37  measures the momentary swivel angle of the saw arm  15 . The swivel angle of the saw arm  15 , together with the diameter of the saw blade  14 , determines how deep the saw blade  14  plunges into the workpiece  18 . The position sensor  38  measures the momentary position of the saw head  12  on the guide rail  11 . The measured quantities are transmitted to the first control unit  27  by the swivel-angle sensor  37  and by the position sensor  38 . 
         [0023]      FIG. 2  shows the device system  10  of  FIG. 1  in a first variant. A cut  41  is made in the workpiece  18  using the device system  10 . The cut  41  has a depth T in a depth direction  42  and it runs in the advancing direction  26  along a cutting line  43  between a first end point E 1  and a second end point E 2 . The cut  41  is made in several partial cuts until the desired cut depth T is reached. In the case of the cut  41  shown in  FIG. 2 , no overcut is possible at the end points E 1 , E 2 , so that the cutting depth  41  at the end points E 1 , E 2  is smaller than the cutting depth T. 
         [0024]    By means of the guide carriage  24 , the saw head  12  is positioned on the guide rail  11  in a starting position X 0 . The starting position X 0  of the saw head  12  is between the first and second end points E 1 , E 2  of the cutting line  43  and it is determined by the position of the swivel axis  17  of the saw arm  15 . The position of the swivel axis  17  in the advancing direction  26  during the swiveling movement of the saw arm  15  around the swivel axis  17  remains unchanged. The starting position X 0  as well as a positive and a negative direction beginning at the starting position X 10  are indicated by the mark  44 . 
         [0025]    The positions of the first and second end points E 1 , E 2  in the advancing direction  26  are prescribed by entering the partial lengths. The distance between the starting position X 0  and the first end point E 1  determines a first partial length L 1 , while the distance between the starting position X 0  and the second end point E 2  determines a second partial length L 2 . Based on the mark  44 , the first partial length L 1  is measured in the positive direction, while the second partial length L 2  is measured in the negative direction. The operator measures the first and second partial lengths L 1 , L 2  and then, using the operating means  32 , he/she enters the measured partial lengths L 1 , L 2  together with the directions of the partial lengths into the remote control unit  28 . The operator enters not only the partial lengths L 1 , L 2  but also the desired depth T of the cut  41  as well as the device parameters such as, for instance, the diameter of the saw blade  14  and the workpiece that is to be processed into the remote control unit  28 . Moreover, the operator indicates whether there should be an overcut at one of the end points E 1 , E 2 , at both end points E 1 , E 2  or at neither of the end points E 1 , E 2 . The control commands for making the cut  41  are generated in the first or second control unit  27 ,  31  on the basis of the partial lengths L 1 , L 2 , on the basis of the device parameters and on the basis of additional information. The cut  41  is made in several consecutive partial cuts in the workpiece  18  until the desired cut depth T is reached. 
         [0026]      FIG. 3  shows the device system  10  of  FIG. 1  in a second variant. A cut  51  is made in the workpiece  18  using the device system  10 . The cut  51  has a depth T in a depth direction  42  and it runs in the advancing direction  26  along a cutting line  52  between a first end point E 11  and a second end point E 12 . The end points E 11 , E 12  of  FIG. 3  differ from the end points E 1 , E 2  of  FIG. 2  in that overcuts are allowed and the cut  51  reaches the depth T at the end points E 11 , E 12 . 
         [0027]    The saw head  12  is positioned by means of the guide carriage  24  on the guide rail  11  in a starting position X 10 . The mark  53  indicates the starting position X 10  of the saw head  12  is between the first and second end points E 11 , E 12  and it is determined by a mark  53  on the device housing  23  of the saw head  12 . The starting position X 10  as well as a positive and a negative direction beginning at the starting position X 10 . 
         [0028]    The positions of the end points E 11 , E 12  in the advancing direction  26  are specified by entering a partial length (value and direction) as well as a total length. The distance between the starting position X 0  and the first end point E 11  determines a first partial length L 11 , while the distance between the first and second end points E 11 , E 12  determines the total length L. The positions of the end points E 11 , E 12  are calculated on the basis of the first partial length L 11 , on the basis of the direction in which the first partial length L 1  is measured, and on the basis of the total length L. Instead of the total length L, the operator can enter a second partial length L 12  (value and direction) between the starting position X 10  and the second end point E 12 . The total length L of the cut  51  results from the sum of the values for the first and second partial lengths |L 11 |+L 12 |. Entering the total length L lends itself whenever the total length L of the cut  51  is prescribed, for instance, in case of a wall opening for a door having a height of 2.30 m. If the total length L is known, only one partial length between the starting position X 10  of the saw head  12  and one of the end points E 11 , E 12  needs to be measured. 
         [0029]    The operator can manually enter the partial lengths L 11 , L 12  or the total length L of the cut  51  by using the operating means  32 . As an alternative, the device system  10  can be connected to a sensor system  62  for the distance measurement via a communication connection  61  (see  FIG. 1 ). The operator measures one of the lengths using the sensor system  62  and the measured length is then transmitted to the first or second control unit  27 ,  31  of the device system  10  via the communication connection  61 . In the case of the embodiment of  FIG. 1 , the sensor system  62  is connected to the second control unit  31  via the communication connection  61 . 
         [0030]    In order to carry out the laser distance measurement, a reflecting and/or scattering surface for the laser beam has to be present at the end point whose length is to be measured. The laser distance measurement can be assisted by an active or passive target object. In another variant, the sensor system  62  for the distance measurement can be integrated into the device system  10 .