Method for controlling a wall saw system during the creation of a separation cut

Abstract

A method for controlling a wall saw system during creation of a separating cut in a workpiece. The wall saw system includes a saw head, a pivotable saw arm, a first saw blade, and a larger second saw blade. The separating cut is performed in a plurality of main cuts, where the parameters of the main cuts (saw blade diameter of the saw blade used, main-cut angle) are defined before the start in a main-cut sequence. After the processing of the separating cut by the first saw blade is concluded, the controlled processing of the separating cut is interrupted by a control unit and the wall saw is moved into a parking position such that all actions of the saw-blade change (swinging out the saw arm, removing the first saw blade, installing the second saw blade, and swinging in the saw arm) can be performed.

Claims

1. A method for controlling a wall saw system, wherein the wall saw system comprises a guide rail and a wall saw with a saw head, a motor-driven feed unit that moves the saw head parallel to a feed direction along the guide rail, a first saw blade having a first saw blade diameter (D.1) and a second saw blade having a second saw blade diameter (D.2), wherein the second saw blade diameter (D.2) is larger than the first saw blade diameter (D.1); and comprising the steps of: creating a separation cut of a final depth (T) in a workpiece of a workpiece thickness (d) between a first end point (E.sub.1) and a second end point (E.sub.2), wherein the first or the second saw blade is fastened to a saw arm of the saw head, the saw arm being pivotable around a pivot axis and the first or the second saw blade is driven around an axis of rotation; wherein, before a start of a processing of the separation cut controlled by a control unit of the wall saw, at least the first saw blade diameter (D.1) of the first saw blade, the second saw blade diameter (D.2) of the second saw blade, positions of the first and second end points in the feed direction, the final depth (T) of the separation cut, and a cutting sequence of m cuts, m>2, are determined; wherein the m cuts of the cutting sequence comprise at least a first cut with a first cutting angle (.sub.1) of the saw arm and the first saw blade diameter (D.1) of the first saw blade used in the first cut, and a subsequent second cut with a second cutting angle (.sub.2) of the saw arm and the second saw blade diameter (D.2) of the second saw blade used in the second cut; wherein, during the processing of the separation cut controlled by the control unit: the first cut is done with the first saw blade fastened to the saw arm, the saw arm being pivoted about the pivot axis in a positive rotational direction calculated from a basic position (0) of the saw arm such that the first cutting angle is a positive angle or the saw arm being pivoted about the pivot axis in a negative rotational direction directed counter to the positive rotational direction calculated from the basic position (0) of the saw arm such that the first cutting angle is a negative angle and the second cut is done with the second saw blade fastened to the saw arm, the saw arm being pivoted about the pivot axis in the positive rotational direction calculated from the basic position (0) of the saw arm such that the second cutting angle is a positive angle or the saw arm being pivoted about the pivot axis in the negative rotational direction calculated from the basic position (0) of the saw arm such that the second cutting angle is a negative angle; and the first cut is done with the saw head moved in a positive feed direction in the direction towards the second end point and the second cut is done with the saw head moved in a negative feed direction in the direction towards the first end point; wherein, after the processing of the first cut of the separation cut controlled by the control unit with the first saw blade the processing of the separation cut is interrupted by the control unit and the wall saw is moved by the control unit and the motor-driven feed unit into a park position; wherein before the start of the processing of the separation cut controlled by the control unit in addition a saw arm length () of the saw arm, defined as a distance between the pivot axis and the axis of rotation, and a distance () between the pivot axis and an upper side of the workpiece are established and transmitted to the control unit, which uses the saw arm length () and the distance () to calculate the park position for the wall saw.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 illustrates a wall saw system with a guide rail and a wall saw;

(2) FIGS. 2A, B illustrate processing of a separation cut between a first and second free end point without barrier;

(3) FIGS. 3A, B illustrate processing of a separation cut between a first and second barrier with a saw blade that is not surrounded by a blade guard;

(4) FIGS. 4A, B illustrate processing of a separation cut between a first and second barrier with a saw blade that is surrounded by a blade guard;

(5) FIGS. 5A-H illustrate the wall saw system of FIG. 1 in creating a separation cut between a first free end point that is a barrier and a second free end point without barrier; and

(6) FIGS. 6A-B illustrate the wall saw system of FIG. 1 in creating a further separation cut between a first free end point without barrier and a second end point that is a barrier.

DETAILED DESCRIPTION OF THE DRAWINGS

(7) FIG. 1 shows a wall saw system 10 with a guide rail 11, a tool device 12 arranged displaceable on the guide rail 11 and a remote control 13. The power tool is configured as a wall saw 12 and comprises a processing unit 14 and a motor-driven feed unit 15. The processing unit is configured as a saw head 14 and includes a machining tool 16 designed as a saw blade, which is attached to a saw arm 17 and is driven by a drive motor 18 about an axis of rotation 19.

(8) To protect the operator, the saw blade 16 is surrounded by a blade guard 21, which is secured by means of a blade guard holder on the saw arm 17. The saw arm 17 is formed from a pivoting motor 22 to pivot about a pivot axis 23. The pivot angle of the saw arm 17 determines with a blade diameter D of the saw blade 16, how deep the blade 16 clips into a workpiece 24 to be processed. The drive motor 18 and the pivoting motor 22 are arranged in a device housing 25. The motor-driven feed unit 15 comprises a guide carriage 26 and a feed motor 27 that in the embodiment is also arranged in the device housing 25. The saw head 14 is fixed on the guide carriage 26 and designed to be displaceable through the feed motor 27 along the guide rail 11 in a feed direction 28. In the device housing 25 in addition to the motors 18, 22, 27 a control unit 29 is arranged for controlling the saw head 14 and the motor-driven feed unit 15.

(9) To monitor the wall saw system 10 and the processing procedure, a sensor device is provided with several sensor elements. A first sensor element 32 is designed as a pivot angle sensor and a second sensor element 33 as a displacement sensor. The pivot angle sensor 32 measures the current pivot angle of the saw arm 17 and the displacement sensor 33 measures the current position of the saw head 14 on the guide rail 11. The measured values are transmitted by the pivot angle sensor 32 and displacement sensor 33 to the control unit 29 and used for controlling the wall saw 12.

(10) The remote control 13 comprises a device housing 35, an input device 36, a display device 37, and a control unit 38 that is arranged in the interior of the device housing 35. The control unit 38 converts the inputs of the input device 36 into control commands and data that are transmitted via a first communication link to the wall saw 12. The first communication link is configured as a wireless and cordless communication link 41 or a communications cable 42. The wireless and cordless communication link is formed in the embodiment as a radio link 41 created between a first radio unit 43 on the remote control 13 and a second radio unit 44 on the power tool 12.

(11) Alternatively, the wireless and cordless communication link 41 can be in the form of an infrared, Bluetooth, WLAN or Wi-Fi connection.

(12) FIGS. 2A, B show the guide rail 11 and the wall saw 12 of the wall saw system 10 of FIG. 1 at the creation of a separation cut 51 in the workpiece 24 of workpiece thickness d. The separation cut 51 has a final depth T and extends in the feed direction 28 between a first end point E.sub.1 and a second end point E.sub.2 A direction parallel to the feed direction 28 is defined as the X direction, wherein the positive X direction is from the first end point E.sub.1 to the second end point E.sub.2, and a direction perpendicular to the X direction into the workpiece 24 is defined as the Y direction and is also called the depth direction.

(13) The end point of a separation cut can be defined as free end point without barrier or as barrier. Both end points can be defined as free end points without barrier, both end points as barrier, or one end point as free end point and the other end point as barrier. An overcut can be allowed at a free end point without barrier. Through the overcut, at the end point the depth of cut reaches the final depth T of the separation cut. In the embodiment of FIGS. 2A, B the end points E.sub.1, E.sub.2 form free end points without barrier, wherein on the free first end point E.sub.1 an overcut is not permissible and on the second end point E.sub.2 there is an overcut.

(14) FIG. 2A shows the saw head 14 in a mounting position X.sub.0 and the saw arm 17 in a basic position of 0. The saw head 14 is positioned by the operator by means of the guide carriage 26 in the mounting position X.sub.0 the guide rail 11. The mounting position X.sub.0 of the saw head 14 lies between the first and second end points E.sub.1, E.sub.2 and is determined by the position of the pivot axis 23 in feed direction 28. The position of the pivot axis 23 is particularly suited as reference position X.sub.Ref for the position monitoring of the saw head 14 and control of the wall saw 12, since the X position of the pivot axis 23 also remains unchanged during the pivoting movement of saw arm 17. Alternatively, another X position on the saw head 14 can be established as reference position, wherein in this case the distance in the X direction to the pivot axis 23 must additionally be known.

(15) The X positions of the first and second end points E.sub.1, E.sub.2 are determined in the embodiment by the entry of partial lengths. The distance between the mounting position X.sub.0 and t be first end point E.sub.1 determines a first partial length L.sub.1 and the distance between the mounting position X.sub.0 and the second end point E.sub.2 a second partial length. Alternatively, the X positions of the end points E.sub.1, E.sub.2 can be established by entering a partial length (L.sub.1 or L.sub.2) and a total length L as the distance between the end points E.sub.1, E.sub.2.

(16) The separation cut 51 is produced in multiple partial cuts until the desired final depth T is reached. The partial cuts between the first and the second end points E.sub.1, E.sub.2 are defined as the main cut and the cutting sequence of the main cut as the main cutting sequence. At the end points of the separation cut an additional corner processing can be performed, which with a barrier is called barrier processing and with a free end point with overcut is called overcut processing.

(17) The main cutting sequence can be determined by the operator, or the control unit of the wall saw system determines the main cutting sequence depending on several boundary conditions. Usually the first main cut, also called precut, is made with a reduced depth of cut and a reduced power of the drive motor to prevent a polishing of the saw blade. The remaining main cuts are normally done with the same depth of cut, but can also have different cut depths. The boundary conditions usually established by an operator include the cut depth of the precut, the power of the precut, and the maximum depth of cut of the remaining main cuts. The control unit can determine the main cutting sequence from these boundary conditions.

(18) The main cuts of a separation cut are done with one saw blade diameter or with two or more saw blade diameters. If multiple saw blades are used, the processing usually starts with the smallest saw blade diameter. To be able to mount the saw blade 16 on the saw arm 17, in the basic position of saw arm 17 the saw blade 16 must be arranged above the workpiece 24. Whether this boundary condition is fulfilled depends on two device-specific sizes of the wall saw system 10: a perpendicular distance between the pivot axis 23 of saw arm 17 and an upper side 53 of the workpiece 24; and the saw arm length of saw arm 17, defined as the distance between the axis of rotation 19 of saw blade 16 and the pivot axis 23 of saw arm 17. If the total of these two device-specific amounts is greater than half the saw blade diameter D/2, the saw blade 16 in the basic position is arranged above the workpiece 24. The saw arm length is a fixed device-specific amount of wall saw 12, whereas the perpendicular distance between the pivot axis 23 and the surface 53 besides the geometry of wall saw 12 also depends on the geometry of the guide rail 11 used.

(19) The saw blade 16 is fastened on a flange on saw arm 17 and in the saw operation is driven by drive motor 18 around the axis of rotation 19. In the basic position of saw arm 17, shown in FIG. 2A, the pivot angle is 0 and the axis of rotation 19 of the saw blade 16 lies in depth direction above pivot axis 23. The saw blade 16 is moved by a pivoting movement of saw arm 17 around the pivot axis 23 from the basic position at 0 into the workpiece 24. During the pivoting movement of saw arm 17, saw blade 16 is driven by drive motor 18 around the axis of rotation 19.

(20) To protect the operator, during operation the saw blade 16 should be surrounded by blade guard 21. Wall saw 12 is operated either with blade guard 21 or without blade guard 21. For processing of the separation cut in the area of end points E.sub.1, E.sub.2, a dismounting of blade guard 21 can be provided. If different saw blade diameters are used for processing the separation cut, different blade guards with corresponding blade guard width are also used,

(21) FIG. 2B shows saw arm 17, which in the negative rotational direction 54 is inclined at negative pivot angle . In the negative rotational direction 54 the saw arm 17 is adjustable between pivot angles from 0 to 180, and in a positive rotational direction 55 counter to the negative rotational direction 54 is adjustable between pivot angles from 0 to +180. The arrangement of saw arm 17 shown in FIG. 2B is identified as pulling if saw head 14 is moved in a positive feed direction 56. If saw head 14 is moved in a negative feed direction 57 counter to the positive feed direction 56, the arrangement of saw arm 17 is called pushing.

(22) The maximum penetration depth of saw blade 16 into workpiece 24 is reached at a pivot angle of 180. The position of the axis of rotation 19 in the X direction and Y direction is shifted by the pivoting movement of saw arm 17 around pivot axis 23. The displacement of pivot axis 19 depends on the saw arm length and pivot axis of saw arm 17. The displacement .sub.x in the X direction is .Math.sin() and the displacement .sub.y in the Y direction is .Math.cos().

(23) The saw blade 16 produces in workpiece 24 a cutting edge in the shape of a circular segment with a height h and width b. The height h of the circular segment corresponds to the penetration depth of saw blade 16 into workpiece 24. The relationship D/2=h++.Math.cos() applies for the penetration depth h, where D designates the saw blade diameter, h the penetration depth of saw blade 16, the perpendicular distance between pivot axis 23 and upper side 53 of workpiece 24, the saw arm length and a the first pivot angle, and for the width b relationship b.sup.2=D/2.Math.8h4h.sup.2=4Dh4h.sup.2=4h.Math.(Dh) applies, where h designates the penetration depth of saw blade 16 into workpiece 24 and D the saw blade diameter.

(24) The control of wall saw 12 during the separation cut depends on whether the end points are defined as barriers, and if there is a barrier whether the processing is done with blade guard 21 or without blade guard 21. With a free end point without barrier, the control of wall saw 12 in the inventive method occurs through upper exit points of saw blade 16 at upper side 53 of workpiece 24. The upper exit points of saw blade 16 can be calculated from the reference position X.sub.Ref of pivot axis 23 in the X direction, displacement .sub.x of axis of rotation 19 in the X direction, and width b. An upper exit point facing the first end point E.sub.1 is designated as first upper exit point 58, and an upper exit point facing the second end point E.sub.2 as second upper exit point 59. For the first upper exit point 58 applies X(58)=X.sub.Ref+.sub.xb/2, and for the second upper exit point 59 applies X(59)=X.sub.Ref+.sub.x+b/2 with b=[h.Math.(Dh)] and h=h (, D).

(25) If the end points E.sub.1, E.sub.2 are defined as barriers, an overrun of the end points E.sub.1, E.sub.2 with wall saw 12 is not possible. In this case the control of wall saw 12 in the inventive method occurs through the reference position X.sub.Ref of pivot axis 23 and the limit of wall saw 12. A distinction is made between a processing without blade guard 21 and a processing with blade guard 21.

(26) FIGS. 3A, B show the wall saw system 10 when producing a separation cut between the first end point E.sub.1 and the second end point E.sub.2, which are defined as barriers, wherein the processing occurs without blade guard 21. In the processing without blade guard 21, a first blade edge 61 facing the first end point E.sub.1 and a second blade edge 62 facing the second end point E.sub.2 form the limit of the wall saw 12.

(27) The X positions of the first and second saw blade edges 61, 62 in the X direction can be calculated from the reference position X.sub.Ref of pivot axis 23, displacement .sub.x of axis of rotation 19 and saw blade diameter D. FIG. 3A shows the wall saw 12 with the saw arm 17 inclined in the negative rotational direction 54 at a negative pivot angle (0 to 180). For the first saw blade edge 61 applies X(61)=X.sub.Ref+.Math.sin()D/2 and for the second saw blade edge 62 applies X(62)=X.sub.Ref+.Math.sin(+)D/2. FIG. 3B shows wall saw 12 with saw arm 17 inclined in a positive rotational direction 55 at a positive pivot angle (0 to +180). For the first saw blade edge 61 applies X(61)=X.sub.Ref+.Math.sin()D/2 and for the second saw blade edge 62 applies X(62)=X.sub.Ref+.Math.sin()+D/2.

(28) FIGS. 4A, B show the wall saw system 10 when creating a separation cut between the first end point E.sub.1 and the second end point E.sub.2, defined as barriers, wherein the processing is done with blade guard 21. In the processing with blade guard 21, a first blade guard edge 71 facing the first end point E.sub.1, and a second blade guard edge 72 facing the second end point E.sub.2, form the limit of wall saw 12.

(29) The X positions of the first and second blade guard edges 71, 72 in the X direction can be calculated from the reference position X.sub.Ref of pivot axis 23, displacement .sub.x of axis of rotation 19 and blade guard width B. FIG. 4A shows the wall saw 12 with saw arm 17 inclined at a negative pivot angle (0 to 180), and a mounted blade guard 21 of blade guard width B. In an asymmetrical blade guard, before the start of the controlled processing the distances of the axis of rotation 19 to the blade guards 71, 72 are determined, wherein the distance to the first blade guard edge 71 is identified as first distance B.sub.a and the distance to the second blade guard edge 72 as second distance B.sub.b.

(30) For the first blade guard edge 71 applies X(71)=X.sub.Ref+.Math.sin()B.sub.a and for the second blade guard edge 72 applies X(72)=X.sub.Ref+.Math.sin()+B.sub.b. FIG. 4B shows the wall saw 12 with the saw arm 17 inclined at positive swivel angle (0 to +180), and the mounted blade guard 21 of the blade guard width B. For the first blade guard edge 71 applies X(71)=X.sub.ref+.Math.sin()B.sub.a and for the second blade guard edge 72 applies X(72)=X.sub.Ref+.Math.sin()+B.sub.b.

(31) FIGS. 2A, B show a separation cut between two end points E.sub.1, E.sub.2, which are defined as free end points without barrier, and FIGS. 3A, B and 4A, B show a separation cut between two end points E.sub.1, E.sub.2, which are defined as barriers. In practice, separation cuts are also possible in which one end point is defined as a barrier and the other end is a free end without barrier, wherein the control of the wall saw with the free end point occurs through the upper exit point of the saw blade and with the barrier through the blade edge (processing without blade guard 21) or the blade guard edge (processing with blade guard 21).

(32) The first upper exit point 58, the first blade edge 61 and the first blade edge guard 71 are summarized under the term first limit of wall saw 12 and the second upper exit point 59, the second blade edge 62 and the second blade guard edge 72 are summarized under the term second limit.

(33) FIGS. 5A-H show the wall saw system 10 of FIG. 1 with the guide rail 11 and wall saw 12 when creating a separation cut of final depth T in the workpiece 24 between a the first end point E.sub.1 that is a barrier and a second end point E.sub.2, that is a free end point without barrier.

(34) The processing of the separation is done with the help of the inventive method for controlling a wall saw system. The separation cut is made in a main cutting sequence of several main cuts until the desired final depth T is reached. The main cutting sequence comprises a precut (zeroed main cut) with a zeroed main cutting angle .sub.0 of the saw arm 17, a zeroed diameter D.sub.0 and a zeroed penetration depth h.sub.0 of the saw blade used, a first main cut with a first main cutting the saw arm 17, a first diameter D.sub.1 and first penetration depth h.sub.1 of the saw blade used, a second main cut with a second main cutting angle .sub.2 of the saw arm 17, a second diameter D.sub.2 and a second penetration depth h.sub.2 of the saw blade used, as well as a third main cut with a third main cutting angle .sub.3 of the saw arm 17, a third diameter D.sub.3 and a third penetration depth h.sub.3 of the saw blade used.

(35) The precut and the first main cut are made by a first saw blade 16.1 with a first saw blade diameter D.1 and a first blade guard 21.1 with a first blade guard width B.1. The zeroed diameter D.sub.0 of the precut and the first diameter D.sub.1 match the first saw blade diameter D.1, and the zeroed width B.sub.0 of the precut and the first width B.sub.1 of the first main cut match the first blade guard width B.1. The second main cut and the third main cut are made by a second saw blade 16.2 with a second saw blade diameter D.2 and a second blade guard 21.2 with a second blade guard width B.2. The second diameter D.sub.2 of the second main cut and the third diameter D.sub.3 of the third main cut match the second saw blade diameter D.2, and the second width B.sub.2 of the second main cut and the third width B.sub.3 of the third main cut match the second blade guard width B.2.

(36) The main cuts of a separation cut are advantageously either done with a pulling saw arm 17 or the saw arm 17 is arranged alternatingly pulling and pushing. The pulling arrangement of saw arm 17 enables a stable guiding of the saw blade during the processing and a narrow kerf. A separation cut in which the saw arm is arranged alternatingly pulling and pushing has the advantage that the nonproductive times necessary for positioning the saw head 14 and pivoting the saw arm 17 are reduced.

(37) In the embodiment of FIGS. 5A-H the processing in all main cuts occurs with the pulling saw arm 17. The processing of the separation cut starts at the second end point E2. After the start of the inventive method the saw head 14 is positioned in a start position X.sub.Start in which the pivot axis 23 has a distance of [h.sub.0(D.sub.0h.sub.0)]+.Math.sin(.sub.0) to the second end point E.sub.2, where h.sub.0=h(.sub.0, D.sub.0)=D.sub.0/2.Math.cos(.sub.0) denotes the penetration depth of the saw blade into the workpiece 24 at the zeroed main cutting angle .sub.0 with zeroed diameter D.sub.0, corresponding to the first saw blade diameter D.1. In the start position the saw arm 17 is pivoted from the basic position 0 in the positive direction of rotation 55 at the positive zeroed main cutting angle .sub.0. The saw head 14 is then moved with the inclined saw arm 17 and rotating first saw blade 16.1 in the negative feed direction 57.

(38) Since the first blade guard 21.1 is mounted, the control of the wall saw 12 at the first end point E.sub.1 occurs through the first blade guard edge 71.1 of the first blade guard 21.1. The saw head 14 is stopped if the pivot axis 23 has a distance of B.sub.1/2.Math.sin(.sub.1) to the first end point E.sub.1. The first width B.sub.1 of the blade guard used corresponds to the first blade guard B.1 width of the first blade guard 21.1. The saw arm 17 is then rotated in the negative direction of rotation 54 at the negative first main cutting angle .sub.1 and the saw head 14 with the saw arm 17 inclined at .sub.1 is moved in the positive feed direction 56 (FIG. 5A). In the embodiment, the transition from the precut to the first partial cut is done without removal of the residual material. Alternatively, the precut can be ended with a complete removal of the residual material with the precut or a partial removal.

(39) The saw head 14 is moved in the positive feed direction 56 until that the pivot axis 23 has a distance of [h.sub.1(D.sub.1h.sub.1)]+.Math.sin(.sub.1) to the second end point E.sub.2, where h.sub.1=h(.sub.1, D.sub.1)=D.sub.1/2.Math.cos(.sub.1) designates the penetration depth of the first saw blade 16.1 into the workpiece 24 at the negative first main cutting angle .sub.1 with the first diameter D.sub.1, which corresponds to the first saw blade diameter D.1. The saw arm 17 is then pivoted in the positive direction of rotation 55 at the positive first main cutting angle .sub.1 and the residual material removed.

(40) To change the saw blade from the first saw blade 16.1 to the second saw blade 16.2, saw head 14 is positioned in a park position X.sub.Park and saw arm 17 is pivoted out from the workpiece 24, wherein saw arm 17 in the embodiment is pivoted into the basic position of 0 (FIG. 5B). The positioning of saw head 14 into the park position and the rotation movement of saw arm 17 can occur in succession or be done simultaneously.

(41) The park position should fulfill various boundary conditions. The first saw blade 16.1 and the first blade guard 21.1 can be dismounted in the park position. The second saw blade 16.2 and the second blade guard 21.2 can be mounted in the park position. Furthermore, the movement path to the positioning of saw head 14 for the second main cut should be as small as possible; ideally, the park position corresponds to the start position for the second main cut.

(42) Since the second end point E.sub.2 is a free end point without barrier, the dismounting of the first saw blade 16.1 and first blade guard 21.1, as well as the mounting of the second saw blade 16.2 and second blade guard 21.2 are easily possible. In the park position shown in FIG. 5B, the pivot axis 23 has a distance of [h.sub.2(D.sub.2h.sub.2)]+.Math.sin(.sub.2) to the second end point E.sub.2, where h.sub.2=h(.sub.2, D.sub.2)=D.sub.2/2.Math.cos(.sub.2) designates the penetration depth of the second saw blade 16.2 into the workpiece 24 at the positive second main cutting angle .sub.2 with the second diameter D.sub.2, which correspond to the second saw blade diameter D.2.

(43) After the mounting of the second saw blade 16.2 and second blade guard 21.2, as well as the resumption of the controlled processing, the wall saw 12 is positioned by the control unit 29 into a resumption position X.sub.Resumption that corresponds to the park position X.sub.Park. In calculating the park position the distance was set such that the second upper exit point 59.2 facing the second end point E.sub.2 of the second saw blade 16.2 after the rotation movement of saw arm 17 at the positive second main cutting angle .sub.2 coincides with the second end point E.sub.2 (FIG. 5C). The downtimes can be reduced by this positioning.

(44) In the resumption position X.sub.Resumption, the saw arm 17 is rotated in the positive direction of rotation 55 at the positive second main cutting angle .sub.2. The saw head 14 is moved with the saw arm 17 inclined at the second main cutting angle .sub.2 and the rotating second saw blade 16.2 in the negative feed direction 57. The transition from the second main cut to the third main cut is done analogously to the transition from the precut to the first main cut with a complete removal of the residual material (FIG. 5D), or alternatively with a partial removal of the residual material or without removal of the residual material. The control of the wall saw is done by means of the first blade guard edge 71.2 of the second blade guard 21.2.

(45) In practice, it is common when cutting a workpiece to perform the last main cut at the maximum pivot angle of the saw arm, in order to remove as much material in the region of the end points as possible. Without limiting the allowable maximum depth of cut the maximum pivot angle is 180 and with restriction the allowable maximum depth of cut of the saw blade can be converted to a maximum pivot swivel angle. In the embodiment, the third main cut corresponds to the last main cut and is done at a third main cutting angle of 180.

(46) The positioning of saw head 14 for the third main cut at the maximum pivot angle of 180 is done by means of the critical angle of 90. The critical angle of 90 must be taken into consideration since the first end point E.sub.1 may not exceed the pivot movement. The pivot axis 23 at the critical angle of 90 has a distance of B.2/2.Math.sin(90)=B.2/2+ to the first end point E.sub.1. The saw arm 17 is then pivoted into the third main cutting angle of 180 (FIG. 5E).

(47) Since the third main cut is the last main cut of the main cutting sequence, before the processing of the last main cut a corner processing of the first end point E.sub.1 is done. For that the saw head 14 is moved with the saw arm 17 inclined at 180 (FIG. 5F) in the negative feed direction 57 until the first blade guard edge 71.2 of the second blade guard 21.2 coincides with the first end point E.sub.1. The corner processing of the first end point E.sub.1 can be improved if the second blade guard 21.2 is dismounted and the corner processing is done without blade guard. Without blade guard the saw head 14 is moved with saw arm 17 inclined at 180 in the negative feed direction 57 until the first saw blade edge 61.2 of second saw blade 16.2 coincides with the first end point E.sub.1.

(48) After the corner processing of the first end point E.sub.1, the third main cut is done with the saw arm 17 inclined at the negative third main cutting angle .sub.3 in the positive the direction 56. The feed movement of saw head 14 is stopped if the pivot axis 23 has a distance of [h.sub.3(D.sub.3h.sub.3)]+.Math.sin(180)==h.sub.3.Math.(D.sub.3h.sub.3)] to the second end point E.sub.2, where h.sub.3=h(.sub.3, D.sub.3)=D.sub.3/2.Math.cos(180)=D.sub.3/2+ is the penetration depth of the saw blade into the workpiece 24 the negative third main cutting angle .sub.3 with the third diameter D.sub.3, which corresponds to the second saw blade diameter D.2. If at the second end point E.sub.2 an overcut is allowed, after the third main cut there is a corner processing of the second end point E.sub.2 (FIG. 5H).

(49) In the separation cut shown in FIGS. 5A-H, the pivoting movement of saw arm 17 occurs at a new main cutting angle in one pivoting movement. With hard materials or less powerful drive motors 18 it can be advantageous for saw blade 16 to perform the pivoting movement of saw arm 17 in at least two steps with interim angles, wherein between the pivoting movements to the interim angles in each case a free cut of saw blade 16 occurs.

(50) FIGS. 6A, 6B show the wall saw system 10 with guide rail 11 and wall saw 12 when creating another separation cut between a first end point E.sub.1, which represents a free end point without barrier, and a second end point E.sub.2 that is a barrier. The control of wall saw 12 at the first end point E.sub.1 occurs through the first upper exit point 59 of the saw blade used and at the second end point E.sub.2 through the first saw blade edge 61 (without blade guard 21) or the first blade guard edge 71 (with blade guard 21).

(51) The cutting sequence comprises a first main cut at a first main cutting angle .sub.1 of saw arm 17, a first diameter D.sub.1 and the first penetration depth h.sub.1 of the saw blade used, as well as a subsequent second main cut at a second main cutting angle .sub.2 of saw arm 17, a second diameter d.sub.2 and a second penetration depth h.sub.2 of the saw blade used.

(52) The first main cut is made by the first saw blade 16.1 and the first blade guard 21.1 and the second main cut is made by the second saw blade 16.2 and second blade guard 21.2. The first diameter D.sub.1 and the first width B.sub.1 of the first main cut match the first saw blade diameter D.1 and the first blade guard width B.1. The second diameter D.sub.2 and the second width B.sub.2 the second main cut match the second blade guard diameter D.2 and the second blade guard width B.2.

(53) The boundary conditions that apply for the park position are: dismounting of the first blade 16.1 and first blade guard 21.1, mounting of the second saw blade 16.2 and second blade guard 21.2, pivoting out of the saw arm 17 with the first saw blade 16.1 from the first main cutting angle .sub.1 into the basic position at 0, and pivoting in of the saw arm 17 with the second saw blade 16.2 from the basic position at 0 into the second main cutting angle .sub.2.

(54) The dismounting of the first saw blade 16.1 and first blade guard 21.1 and the mounting of the second saw blade 16.2 and second blade guard 21.2 occur in the basic position of saw arm 17 at 0. If the second end point E.sub.2 is a barrier as in the embodiment, before the start of the controlled processing a mounting distance .sub.mount is additionally established. The mounting distance .sub.mount assures there is a sufficient distance for the operator between the barrier and the saw blade and between the barrier and the blade guard to grasp the saw blade and blade guard; a suitable mounting distance is, for example, 10 cm.

(55) With the processing with blade guard, in principle a minimum distance to the second end point (E.sub.2) of B.sub.b.1+.sub.mount for the first blade guard 21.1 and B.sub.b.2 +.sub.mount for the second blade guard 21.2 is necessary. Since the first blade guard width B.1 is smaller than the second blade guard width B.2, with symmetrical blade guards it is sufficient to consider the second blade guard width B.2 in the calculation of the minimum distance for the mounting; with asymmetrical blade guards, both minimum distances must be considered. The pivot axis 23 must have a distance of maximum value [B.sub.b.1+.sub.mount, B.sub.b.2+.sub.mount] to the barrier at E.sub.2 (FIG. 6A).

(56) The necessary distances to the pivoting out of the first saw blade 16.1 and pivoting in of the second saw blade 16.2 at the second end point E.sub.2 depend on the first main cutting angle .sub.1 of the first main cut and the second main cutting angle .sub.2 of the second main cut. A distinction must be made between negative main cutting angles of 180 to 0, positive main cutting angle of 0 to 90 and positive main cutting angle of 90 to 180. For positive main cutting angles of 90 to 180 the critical angle of +90 must be considered, since the barrier at the second end point E.sub.2 may not be exceeded in the pivoting movement. The pivot axis 23 at the critical angle of +90 has a distance to the second end point E.sub.2 of B.sub.b.1+.Math.sin(90)=B.sub.b.1+for the first blade guard 21.1 and B.sub.b.2+sin(90)=B.sub.b.2+for the second blade guard 21.2 (FIG. 6B).

(57) At negative first main cutting angles .sub.1 of 180 to 0, the pivoting out of the first saw blade 16.1 into the basic position at 0 occurs on the side facing away from the second end point E.sub.2 and the displacement is negative. For negative second main cutting angles .sub.2, positive second main cutting angles .sub.2 of 0 to 90 and positive second main cutting angles .sub.2 of 90 to 180, different distances result.

(58) At negative second main cutting angles .sub.2, the pivoting in of the second saw blade 16.2 occurs at the side facing away from the second end point E.sub.2 and the distance necessary for the pivoting in is smaller than the minimum distance to the mounting; the control unit 29 chooses as park position for wall saw 12 the maximum value of [B.sub.b.1+.sub.mount, B.sub.b.2+.sub.mount]. At positive second main cutting angles .sub.2 between 0 and 90, for the pivoting in of the second saw blade 16.2 a distance of the pivot axis 23 to the barrier at E.sub.2 of B.sub.b.2+.Math.sin(.sub.2) is necessary and the control unit 29 chooses as park position for the wall saw 12 the maximum value of (B.sub.b.1+.sub.mount, B.sub.b.2+.sub.mount, B.sub.b.2+.Math.sin(.sub.2)] for 0<.sub.290. At positive second main cutting angles .sub.2 between 90 and 180, the distance necessary for the pivoting in of the second saw blade 16.2 of the pivot axis 23 to barrier B.sub.b.2+.Math.sin(90)=B.sub.b.2+.Math. and the control unit 29 chooses as park position for wall saw 12 the maximum value of [B.sub.b.1+.sub.mount, B.sub.b.2+.sub.mount, B.sub.b.2+.Math.sin(90)] for 90<.sub.2180.

(59) At positive first main cutting angle .sub.1 of 0 to 90, the pivoting out of the first saw blade 16.1 to the basic position occurs on the side facing the second end point E.sub.2. For the pivoting out of the first saw blade 16.1 a distance of the pivot axis 23 of B.sub.b.1+.Math.sin(.sub.1) to the barrier is necessary. For negative second main cutting angles .sub.2, positive second main cutting angles .sub.2 of 0 to 90 and positive second main cutting angles .sub.2 of 90 to 180, different distances result.

(60) At negative second main cutting angles .sub.2, the pivoting in of the second saw blade 16.2 occurs at the side facing away from the barrier and the control unit 29 chooses as park position for wall saw 12 the maximum value of [B.sub.b.1+.sub.mount, B.sub.b.2+.sub.mount, B.sub.b.1+.Math.sin(.sub.1)]. At positive second main cutting angles .sub.2 from 0+ to 90, for the pivoting in of the second saw blade 16.2 a distance of the pivot axis 23 to the barrier of B.sub.b.2+.Math.sin(.sub.2) is necessary and the control unit 29 chooses as park position for the wall saw 12 the maximum value of [B.sub.b.1+.sub.mount, B.sub.b.2+.sub.mount, B.sub.b.1+.Math.sin(.sub.1), B.sub.b.2+.Math.sin(.sub.2)]. At positive second main cutting angles .sub.2 between 90 and 180, the distance necessary for the pivoting in of the second saw blade 16.2 of the pivot axis 23 to the barrier of B.sub.b.2+.Math.sin(90)=B.sub.b.2+.Math. is necessary and the control unit 29 chooses as park position for wall saw 12 the maximum value of [B.sub.b.1+.sub.mount, B.sub.b.2+.sub.mount, B.sub.b.2+.Math.sin(90)].

(61) At positive first main cutting angle .sub.1 of 90 to 180, the pivoting out of the first saw blade 16.1 to the basic position occurs on the side facing the second end point E.sub.2. For the pivoting out of the first saw blade 16.1 a distance of the pivot axis 23 of B.sub.b.1+.Math.sin(90)=B.sub.b.1+ to the barrier at E.sub.2 is necessary. For negative second main cutting angles .sub.2, positive second main cutting angles .sub.2 of 0 to 90 and positive second main cutting angles .sub.2 of 90 to 180, different distances result.

(62) At negative second main cutting angles .sub.2, the pivoting in of the second saw blade 16.2 occurs at the side facing away from the barrier and the control unit 29 chooses as park position for wall saw 12 the maximum value of [B.sub.b.1+.sub.mount, B.sub.b.2+.sub.mount, B.sub.b.1+.Math.sin(90)]. At positive second main cutting angles .sub.2 from 0 to 90, for the pivoting in of the second saw blade 16.2 a distance of the pivot axis 23 to the barrier of B.sub.b.2+.Math.sin(.sub.2) is necessary and the control unit 29 chooses as park position for the wall saw 12 the maximum value of [B.sub.b.1+.sub.mount, B.sub.b.2+.sub.mount, B.sub.b.1+.Math.sin(90), B.sub.b.2+.Math.sin(.sub.2)]. At positive second main cutting angles .sub.2 of 90 to 180, the distance necessary for the pivoting in of the second saw blade 16.2 of the pivot axis 23 to the barrier of B.sub.b.2+.Math.sin(90)=B.sub.b.2+.Math. is necessary and the control unit 29 chooses as park position for wall saw 12 the maximum value of B.sub.b.1+.sub.mount, B.sub.b.2+.sub.mount, B.sub.b.1+.Math.sin(90), B.sub.b.2 +.Math.sin(90)].

(63) If processing of the first and/or second partial cut is done without blade guard, the second saw blade edge 62 instead of the second saw blade edge 72 is used for calculating the minimum distances for the park position and the second saw blade width B.2 will replace the saw blade diameter D.2 of the second saw blade 16.2.

(64) In the separation cuts shown in FIGS. 5A-H and FIGS. 6A, B the pivoting movement of saw arm 17 into the main cutting angle occurs in a pivoting movement. With hard materials or less powerful drive motors 18 it can be advantageous for the saw blade to perform the pivoting movement of saw arm 17 in at least two steps with interim angles, wherein between the pivoting movements to the interim angles in each case a free cut of the saw blade occurs.