Enhanced brake for a ground sawing machine
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- HUSQVARNA AB
- Filing Date
- 2024-06-17
- Publication Date
- 2026-05-13
Smart Images
Figure SE2024050591_09012025_PF_FP_ABST
Abstract
Description
[0001] TITLE
[0002] Enhanced brake for a ground sawing machine
[0003] TECHNICAL FIELD
[0004] The present disclosure relates to a ground sawing machine comprising a frame supported by rear wheels and front wheels arranged to move the ground sawing machine over a surface. At least one motor and a saw blade are mounted to the frame, where at least one motor is arranged to propel the saw blade to cut against the surface. The pointing direction relative the surface of the rear wheels and / or the front wheels is adjustable by means of an electrically controlled actuator.
[0005] BACKGROUND
[0006] A self-propelled floor saw can be used to cut into surfaces such as roads and concrete slabs. During setup and operation of the saw, an operator walks behind the saw to control the direction, cutting speed, cutting depth and other operating conditions under which the saw operates. The saw includes a plurality of wheels allowing the saw to move along the surface and a frame supported by the wheels on which is mounted a motor or other power supply for operating a saw blade and often for driving one or more driven wheels to move the saw along the surface.
[0007] One or more handles extend behind the saw about the level of an operator's hands to allow the operator to manually position and guide the saw. Typically, the saw blade is located at the front of the saw and handles extend behind the saw. For a typical straight cut, the operator aligns the saw blade and often a cutting guide with the intended cutting path. The saw is maneuvered with the saw blade raised above the concrete until the blade and cutting guide are aligned with the cutting path. As the saw blade engages the concrete or other surface to be cut, the blade cuts into the concrete to the desired depth, such as the depth selected by the operator. At the desired depth, the drive wheels are engaged to propel the saw forward to cut the desired slot or groove, which typically follows a straight kerf.
[0008] Only relying on a braking effect of a motor that is connected to one or more driven wheels may be insufficient in order to avoid undesired movement of a ground sawing machine when not in operation. It is necessary that ground sawing machines are equipped with an efficient parking brake that is uncomplicated and suitably can be retro-fitted to existing concrete saws.
[0009] It is also desired that ground sawing machines can obtain a high degree of maneuverability and be easily controlled by an operator. This is the case both during a cutting operation and when transporting the ground sawing machine between cutting operations.
[0010] SUMMARY
[0011] An objective of the present disclosure is to provide a ground sawing machine with an efficient parking brake function. Another objective is to provide a ground sawing machine with increased maneuverability and easily handled control.
[0012] The objective is at least in part obtained by a ground sawing machine comprising a control unit and a frame supported by rear wheels and front wheels arranged for enabling moving the ground sawing machine over a surface. At least one motor arrangement and a saw blade are mounted to the frame, a first motor arrangement being arranged to propel the saw blade to cut against the surface, where a rear wheel turning angle is adjustable by means of an actuator that is adapted to pivot a rear wheel axle. The ground sawing machine comprises at least one brake block that is fixed or fixedly mounted relative the frame, where the actuator is adapted to pivot the rear wheel axle such that at least one rear wheel comes into braking engagement with the brake block.
[0013] In this manner, a parking brake is provided where the ground sawing machine can be reliably braked and left when not in use without risking the ground sawing machine moving in an uncontrolled manner. Furthermore, one or more brake blocks can be added to existing machines, requiring only minor modifications to allow said brake blocks to be mounted in a correct position.
[0014] According to some aspects, the actuator is an electrically controlled actuator. According to some further aspects, the control unit is adapted to control the actuator in dependence of activation of control means. This means that the actuator can be accurately controlled in a reliable manner. According to some aspects, the control unit is adapted to control the actuator in dependence of activation of brake control means, where the control unit is adapted to control the actuator to automatically pivot the rear wheel axle such that at least one rear wheel comes into braking engagement with the brake block upon activation of the brake control means. This means that the brake is activated by an operator that activates the braking control means, for example by pressing a brake button on the sub-panel.
[0015] According to some aspects, the control unit is adapted to control the actuator to automatically pivot the rear wheel axle such that at least one rear wheel into braking engagement with the brake block when the ground sawing machine is stopped and / or turned off. This means that the brake is activated automatically when the ground sawing machine is turned off, for example upon activation of stop control means, for example in the form of a stop button on the sub-panel.
[0016] According to some aspects, when the ground sawing machine is started and / or turned on, the control unit is adapted to control the actuator to automatically reset the rear wheel turning angle to a previous value that was set before the actuator was controlled to pivot the rear wheel axle such that at least one rear wheel comes into braking engagement with the brake block. This means that the brake is de-activated automatically and the rear wheel axle re-set to its last operational setting when the ground sawing machine is turned on, for example upon activation of a start control means, for example in the form of a start button on the sub-panel or remote-control unit.
[0017] According to some aspects the control unit is configured to detect that at least one rear wheel is in braking engagement with the brake block. This way the control unit can make sure that the parking brake is engaged. The control unit can detect that at least one rear wheel is in braking engagement with the brake block by monitoring a current consumption of the actuator or by monitoring an output signal from a sensor such as a position sensor, and angle sensor, or a pressure sensor. The monitoring of the parking brake function by the control unit can be conditioned on that the rear wheel axle has a rear wheel turning angle within a given parking brake angle range. According to some aspects, the control unit is adapted to control the actuator in dependence of activation of steering control means such that the wheel turning angle is set at desired value. This enables an operator to set a desired position for the rear wheel axle using the steering control means, for example two buttons or a toggle switch on the sub-panel or remote-control unit.
[0018] According to some aspects, the control unit is adapted to control the actuator in dependence of activation of automatic course maintaining control means such that the wheel turning angle is automatically set during operation such that the ground sawing machine moves in a predetermined direction. In this manner, the ground sawing machine can be set in an automatic mode such that a movement in a predetermined direction is maintained, compensating for course change due to blade cutting resistance and other error sources
[0019] According to some aspects, the control unit is adapted to limit the setting of the wheel turning angle such that no wheel comes into braking engagement with the brake block during operation. In this manner it is avoided that a brake is activated, i.e., that at least one rear wheel comes into braking engagement with the brake block, during operation of the ground sawing machine.
[0020] According to some aspects, said brake block is at least partly made in metal. This enables a durable and easily manufactured brake block.
[0021] According to some aspects, said brake block comprises a brake block engagement surface that is adapted to engage a wheel outer surface. According to some aspects, the brake block engagement surface is constituted by a friction layer that is made in at least one of Kevlar, glass, carbon fiber and rubber. In this manner, the brake effect of a rear wheel pressed against an engagement surface can be enhanced.
[0022] According to some aspects, each brake block is releasably mounted to a brake block holder that is attached to the frame. This means that a worn or damaged brake block can be easily exchanged if necessary. According to some aspects, each brake block has a complementary shape with respect to a wheel outer surface where the brake block is adapted to contact the wheel outer surface. In this way, a brake block engagement surface is optimized to provide a large contact surface against the corresponding wheel outer surface.
[0023] According to some aspects, each brake block has a tangential extension with respect to a wheel outer surface where the brake block is adapted to contact the wheel outer surface. In this way, the brake blocks can be manufactured in an uncomplicated manner and have a triangular shape that is suitable for efficient storage during shipping and handling, while the brake block engagement surface provides a sufficient contact surface against the corresponding wheel outer surface.
[0024] According to some aspects, the rear wheels are adapted to be propelled by a second motor arrangement. According to further some aspects, the motor arrangement comprises a first electric or hydraulic motor drivably connected to a first rear wheel and a second electric or hydraulic motor drivably connected to a second rear wheel.
[0025] According to some aspects, the control unit is adapted to control the first motor and the second motor to propel the corresponding first rear wheel and second rear wheel independently and with either the same rotational velocity or with different rotational velocities. This enables independent control of the rear wheels.
[0026] The control unit is optionally also adapted to control the first motor and the second motor to propel the corresponding first rear wheel and second rear wheel at a rotational velocity difference corresponding to a difference in turning radii of the first rear wheel and the second rear wheel, i.e., in dependence of the rear wheel turning angle. This way wheel scrubbing during turning can be reduced, which is an advantage.
[0027] The control unit can also be arranged to obtain data indicative of a desired steering angle of the ground sawing machine and to coordinate control of the rear wheel turning angle and a rotational velocity difference of the first rear wheel and second rear wheel to steer the machine according to the desired steering angle. This increases the maneuverability of the machine, as will be discussed in more detail below. This object is also obtained by means of other types of ground sawing machine as described herein.
[0028] For example, this object is also obtained by means of a ground sawing machine comprising a control unit and a frame supported by rear wheels and front wheels arranged for enabling moving the ground sawing machine over a surface. A saw blade is mounted to the frame, and a first motor arrangement is arranged to propel the saw blade to cut against the surface, where the rear wheels are adapted to be propelled by a second motor arrangement that comprises a first motor drivably connected to a first rear wheel and a second motor drivably connected to a second rear wheel. The rear wheels are attached to a rear wheel axle, and a rear wheel turning angle is adjustable by means of an actuator that is adapted to pivot the rear wheel axle. The control unit is adapted to control the first motor and the second motor to propel the corresponding first rear wheel and second rear wheel independently and with either the same rotational velocity or with different rotational velocities.
[0029] In this manner, different types of alterations can easily be made to the ground sawing machine's movement direction.
[0030] For example, this object is also obtained by means of a ground sawing machine comprising a control unit and a frame supported by rear wheels and front wheels arranged for enabling moving the ground sawing machine over a surface. At least one motor arrangement and a saw blade are mounted to the frame, a first motor arrangement being arranged to propel the saw blade to cut against the surface, where the rear wheels are attached to a rear wheel axle. A rear wheel turning angle is adjustable by means of an actuator that is adapted to pivot the rear wheel axle. The ground sawing machine comprises a remote-control unit, where the control unit is adapted to control the ground sawing machine's movement direction upon activation of steering control means comprised in the remote-control unit by controlling the actuator that is adapted to pivot the rear wheel axle such that the wheel turning angle is set at desired value.
[0031] In this way, it is possible to control the movement of the ground sawing machine during operation by means of the remote-control unit, for example an operator can compensate for course changes due to blade cutting resistance and other error sources by means of the remote-control unit.
[0032] The control unit of the ground sawing machine and / or the remote control unit can be configured to execute an automated sequence of maneuver commands comprising control of the actuator and / or control of drive wheel speed in response to an operator command. This way the machine can be made to perform a turning maneuver and end up facing in an opposite direction, move sideways a given distance, or perform some other translation and rotational movement from a starting position to an ending position in a predetermined manner. The operator can conveniently trigger such automated sequences of maneuvers to reposition the machine. The sequence of maneuver commands may, e.g., comprise coordinated control of the rear axle pivoting actuator and the drive motors on the machine.
[0033] BRIEF DESCRIPTION OF THE DRAWINGS
[0034] The present disclosure will now be described more in detail with reference to the appended drawings, where:
[0035] Figure 1 shows a schematic side view of a ground sawing machine;
[0036] Figure 2 shows a schematic perspective view of the ground sawing machine with the engine omitted;
[0037] Figure 3 shows a first schematic bottom view of the ground sawing machine with the rear wheels at first wheel turning angle;
[0038] Figure 4 shows a second schematic bottom view of the ground sawing machine with the rear wheels at second wheel turning angle;
[0039] Figure 5 shows a schematic front view of a control panel;
[0040] Figure 6A shows a schematic side view of an unbraked rear wheel according to a first example; Figure 6B shows a schematic side view of a braked rear wheel according to the first example;
[0041] Figure 7A shows a schematic side view of an unbraked rear wheel according to a second example;
[0042] Figure 7B shows a schematic side view of a braked rear wheel according to the second example;
[0043] Figure 8A shows a schematic cut-open view of a first type of actuator;
[0044] Figure 8B shows a schematic cut-open view of a second type of actuator;
[0045] Figure 9 shows a schematic view of the rear wheels and the rear wheel axle;
[0046] Figure 10 illustrates an example control unit;
[0047] Figure 1 1 shows an example automated maneuver by a ground sawing machine.
[0048] DETAILED DESCRIPTION
[0049] The inventive concept will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the inventive concept are shown. This inventive concept may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art. Like numbers refer to like elements throughout the description. Any step or feature illustrated by dashed lines should be regarded as optional.
[0050] In Figure 1 -4, there is illustrated a ground sawing machine 30, such as for example a concrete sawing machine or road sawing machine, that comprises a control unit 210 and a frame 32 supported by rear wheels 34a, 34b and front wheels 36a, 36b arranged for enabling moving the ground sawing machine over a surface 38, for example a concrete surface. At least one motor arrangement 40; 6A, 6B and a saw blade 2 are mounted to the frame 32, and a first motor arrangement 40 is arranged to propel the saw blade 2 to cut against the surface 38. According to some aspects, the saw blade 2 is a diamond saw blade.
[0051] An example control unit 210 will be discussed in more detail below in connection to Figure 10.
[0052] According to some aspects, the rear wheels 34a, 34b are adapted to be propelled by a second motor arrangement 6a, 6b, and according to some further aspects, the second motor arrangement comprises a first motor 6a drivably connected to a first rear wheel 34a and a second motor 6b drivably connected to a second rear wheel 34b. According to some aspects, the second motor arrangement is constituted by electric motors or hydraulic motors that for example are electrically powered. In the example described, the rear wheels 34a, 34b will be regarded as drive wheels, although there of course exist other alternatives for which wheels constitute drive wheels. This provides a reliable independent propulsion of the rear wheels 34a, 34b.
[0053] Alternatively, the first motor arrangement 40 may provide power both to rotate the saw blade 2 and to operate, through a transmission, the drive wheels, here the rear wheels 34a, 34b. The first motor arrangement may be constituted by an electric motor, a hydraulic motor or a combustion engine, for example powered by means of gas, diesel or propane.
[0054] The saw blade 2 can be mounted on the right side of the frame 32, for right hand saw cut, or on the left side of the frame 32 for left-hand saw cut, offset from a center line 42. A blade guard 3 typically extends over at least the upper portion of the saw blade to provide a suitable protection against personal injury and to help control debris and slurry spread that may be produced during cutting.
[0055] According to some aspects, handles 15 enable an operator to move the ground sawing machine 30 by operating a drive assembly to propel the ground sawing machine 30 in a movement direction D, for example a forward movement direction, where cutting along a cut line 18 is maintained by keeping the ground sawing machine 30 in the movement direction D. Movement of the ground sawing machine 30 through the rear wheels 34a, 34b can be controlled through a drive control 44 on a console 17. The console 17 comprises a sub-panel 200 that will be described more in detail later.
[0056] The cutting speed or forward progress can be controlled in part by controlling the power applied to the rear wheels 34a, 34b through the second motor arrangement 6a, 6b. Blade depth can be controlled by suitable positioning of a hinged front axle assembly 11 , which may hydraulically raise and lower the front end of the saw. The front axle assembly 1 1 is supported on the concrete or other surface through the front wheels 36a, 36b. The front axle assembly pivots downward away from, and upward toward, the saw frame 32 when adjusted, thereby raising and lowering the saw blade 2.
[0057] The rear wheels 34a, 34b are mounted to a movable rear wheel axle 46 enabling the position of the rear wheels 34a, 34b to be movable relative to the frame 32 so as to change their direction of drive relative to a front-to-back direction of the frame. A rear wheel turning angle cp is adjustable by means of an actuator 56 that is adapted to pivot a rear wheel axle 46.
[0058] The rear wheel axle 46 is pivotally coupled to the frame 32 through a connection such as that provided by spindle 48 supported by a bearing. The rear wheel axle 46, with the rear wheels 34a, 34b, can pivot about the spindle 48. Pivoting of the axle with the drive wheels allows the direction of motive force produced through the rear wheels 34a, 34b to be changed relative to the frame 32. The connection provided by the spindle 48 is a form of a swivel coupling defining a pivot point, but other configurations can be used as well, for example bearing surfaces, low friction surfaces, or the like. The pivoting coupling of the rear wheel axle 46 relative to the frame 32 can be located at another position than at the center of the axle as shown in Figure 3. For example, the pivot point 48 can be off-center, and can be closer to one drive wheel than to the other, and the pivot axis can be positioned above a wheel.
[0059] According to the present disclosure, with reference in particular to Figure 3, Figure 4, Figure 6A and Figure 6B, the ground sawing machine 30 comprises at least one brake block 101 , 102 that is fixed or fixedly mounted relative the frame 32, where the actuator 56 is adapted to move at least one rear wheel 34a, 34b to come into braking engagement with the brake block 101 , 102. In the present example there are two brake blocks, a first brake block 101 for the first rear wheel 34a and a second brake block 102 for the second rear wheel 34a. Generally, there is at least one brake block, and this is indicated in Figure 3 and Figure 4 by the second brake block 102 and a corresponding brake block holder being indicated by dashed lines.
[0060] In this manner, a parking brake is provided where the ground sawing machine 30 can be reliably braked and left when not in use without risking the ground sawing machine 30 moving in an uncontrolled manner. Furthermore, one or more brake blocks 101 , 102 can be added to existing machines, requiring only minor modifications to allow said brake blocks 101 , 102 to be mounted in a correct position.
[0061] According to some aspects, each brake block 101 , 102 is fixedly but releasably mounted to a brake block holder 103, 104 that is attached to the frame 32. This means that a worn or damaged brake block can be easily exchanged if necessary. Alternatively, each brake block 101 , 102 is welded to the frame, i.e. fixed to the frame, or bolted to the fame, being rigidly and securely connected to the frame 32.
[0062] According to some aspects, with reference to Figure 8A and Figure 8B, the actuator 56 is an electrically controlled actuator. The actuator 56 may be any suitable linear actuator for moving a rod 700, 704 over a continuous linear distance or over a series of discrete linear distances to achieve the desired pivoting movement of the rear wheel axle 46. This means that the actuator can be accurately controlled in a reliable manner.
[0063] A hydraulic actuator can of course also be used with the same or at least similar technical effect.
[0064] According to some aspects, as illustrated in Figure 8A, the actuator 56A is a linear actuator that comprises a threaded rod 700 that engages inner threads of a nut part 702, where the threaded rod 700 is displaced by means of rotation of the nut part 702. The nut part 702 is suitably rotated by means of an electric actuator motor 703 that for example can be a step-motor with a controlled position. A control unit 210 comprised in the ground sawing machine 30 can be used to control the actuator motor 703. The nut part 702, the actuator motor 703 and a part of the rod are preferably positioned within an actuator housing 701 . Here the threaded rod 700 constitutes an extending actuator arm 310 as indicated in Figure 3 and Figure 4.
[0065] According to some aspects, as illustrated in Figure 8B, the actuator 56B is a linear actuator that comprises a threaded rod 706 that engages inner threads of a nut part 704, where the nut part 704 is displaced by means of rotation of the threaded rod 706. The threaded rod 706 is suitably rotated by means of an electric actuator motor 707 that for example can be a step-motor with a controlled position. The control unit 210 can be used to control the actuator motor 707. The threaded rod 706, the actuator motor 707 and a part of the nut part 704 are preferably positioned within an actuator housing 705. Here the nut part 704 constitutes an extending actuator arm 310 as indicated in Figure 3 and Figure 4.
[0066] The actuator can also be based on other principles, the extending actuator arm could alternatively be connected to a hydraulic cylinder comprised in the actuator 56. According to some aspects, the actuator 56 is a manually controlled actuator, and is according to some further aspects displaced by manually turning a nut or a threaded rod, for example in a manner corresponding to the electrically controlled actuator as described above. An operator may then turn a knob or similar that is connected to the nut or a threaded rod to control such a manually controlled actuator.
[0067] The at least one rear wheel 34a, 34b is retained in braking engagement with said brake block 101 , 102 by means of the actuator 56, in particular if the actuator is a linear actuator that comprises a threaded part that engages inner threads of a nut part as described above. An electric motor, such as the actuator motors 703, 707 described above, as well as a hydraulic motor, also presents a resistance that provides a retaining force to keep the at least one rear wheel 34a, 34b in braking engagement with said brake block 101 , 102 when the motor in question is disengaged.
[0068] It is appreciated that the front wheels 36a, 36b of the ground sawing machine 30 can also be pivotable by a front axle pivoting actuator (not shown in the Figures) and thus brought into contact with a brake block in the same way as the rear wheels. In other words, there is disclosed herein a ground sawing machine 30 comprising a control unit 210 and a frame 32 supported by rear wheels 34a, 34b and front wheels 36a, 36b arranged for enabling moving the ground sawing machine over a surface 38, where at least one motor arrangement 40; 6A, 6B and a saw blade 2 are mounted to the frame. A first motor arrangement 40 is arranged to propel the saw blade 2 to cut against the surface 38, where a front wheel turning angle is adjustable by means of a front axle pivoting actuator that is adapted to pivot a front wheel axle. The ground sawing machine 30 comprises at least one brake block that is fixed or fixedly mounted relative the frame 32, where the front axle pivoting actuator is adapted to pivot the front wheel axle such that at least one front wheel 36a, 36b comes into braking engagement with the brake block. However, for sake of simplicity, only pivotable rear axles are discussed herein, although it is understood that similar techniques can be realized based on a pivotable front wheel axle.
[0069] Suitable linkages 31 1 are provided between the extending actuator arm 310 and the rear wheel axle 46 to achieve the desired movement of the rear wheel axle 46. The actuator 56 can move the rear wheel axle 46 through a significant angle both in a positive or clockwise direction and in a negative or counter-clockwise direction relative to the precisely transverse position of the rear wheel axle 46 as shown in Figure 3 and Figure 4.
[0070] According to some aspects, the rear wheels 34a, 34b have a common wheel rotation axis 35, where the actuator 56 is adapted to pivot the rear wheel axle 46 about a pivot axis 37 that is perpendicular to the wheel rotation axis 35. This provides a robust and reliable configuration for having the rear wheel axle 46 pivoted.
[0071] According to some aspects, the control unit 210 is adapted to control the actuator 56 in dependence of activation of control means 203, 204, 205, 206, 207. The control means are for example in the form of buttons provided on the sub-panel 200, constituting an onboard interface. The control means 203, 204, 205, 206, 207 can additionally, or alternatively, be provided at a remote-control unit 50 that is schematically indicated in Figure 1 . This means that, according to some aspects, an operator can use the sub-panel 200 and / or the remote-control unit 50 to control the operation of the ground sawing machine 30. According to some aspects, the control unit 210 is adapted to control the actuator 56 in dependence of activation of a brake control means 207, where the control unit 210 is adapted to control the actuator 56 to automatically pivot the rear wheel axle 46, such that at least one rear wheel 34a, 34b comes into braking engagement with the brake block 101 , 102 upon activation of the brake control means 207. This means that the brake is activated by an operator that activates the braking control means 207, for example by pressing a brake button 207 on the sub-panel 200. Here, and in all other examples, activating a function, for example by pressing a button, can be performed by means of the sub-panel 200 and / or by means of the remote-control unit 50. Figure 5 thus illustrates examples of control means for both the sub-panel 200 and for the remote-control unit 50. In practice, in cases where there is both a sub-panel 200 and a remote-control unit 50, these can have the same control means or different sets of control means. Either the sub-panel 200 or the remote-control unit 50 can be equipped to provide a larger number of control possibilities than the other.
[0072] According to some further aspects, if the ground sawing machine 30 is moving when the brake is activated as described above, the control unit 210 is adapted to control the second motor arrangement 6a, 6b to slow down and stop such that the ground sawing machine 30 is not moving when the actuator 56 is controlled to pivot the rear wheel axle 46, such that at least one rear wheel 34a, 34b comes into braking engagement with the brake block 101 , 102. This means that the control unit 210 is adapted to determine whether the ground sawing machine 30 is moving or not, and this may for example be achieved by means of checking present control signaling from the control unit 210 to the second motor arrangement 6a, 6b, possibly in combination with feedback from the second motor arrangement 6a, 6b in the form of operation status. Braking the ground sawing machine 30 when it is moving is thus generally performed by controlling the second motor arrangement 6a, 6b to slow down and eventually to stop if that is desired. In this way it is avoided that the rear wheel axle 46 is pivoted to a brake position when the ground sawing machine 30 is moving.
[0073] According to some aspects, control unit 210 is adapted to control the actuator 56 to automatically pivot the rear wheel axle 46, such that at least one rear wheel 34a, 34b comes into braking engagement with the brake block 101 , 102 when the ground sawing machine 30 is stopped and / or turned off. This means that the brake is activated automatically when the ground sawing machine 30 is turned off, for example upon activation of stop control means 203, for example in the form of a stop button 203 on the sub-panel 200 or the remote-control unit 50.
[0074] It may be desired to verify that the parking brake has actually been engaged. I.e., to ensure that the ground sawing machine has been properly immobilized following control of the actuator to engage the parking brake. Thus, according to some aspects the control unit is configured to detect that at least one rear wheel 34a, 34b is in braking engagement with the brake block 101 , 102. This detection can be achieved in several different ways, and the control unit may use one or more methods for the detection. A more reliable detection is achieved by using more than one method to detect that the parking brake is engaged. The control unit can for instance be configured to detect that the at least one rear wheel 34a, 34b is in braking engagement with the brake block 101 , 102 at least in part by monitoring a current or power consumption of the actuator 56, which will peak when the wheel engages the brake block.
[0075] The control unit 210 can also be configured to detect that the at least one rear wheel 34a, 34b is in braking engagement with the brake block 101 , 102 at least in part by monitoring an output signal from a position sensor arranged in connection to the at least one rear wheel 34a, 34b, the brake block 101 , 102, and / or the rear wheel axle (46). This position sensor will provide an output signal that is indicative of the state of the rear axle. Thus, by comparing the output from the position sensor the control unit can determine whether the parking brake function is engaged or not.
[0076] A pressure sensor or load cell can also be used to verify that the wheel engages the brake block. Thus, according to some aspects the control unit 210 is configured to detect that the at least one rear wheel 34a, 34b is in braking engagement with the brake block 101 , 102 at least in part by monitoring an output signal from a pressure sensor arranged in connection to the at least one rear wheel 34a, 34b and / or the brake block 101 , 102. The pressure sensor can, for instance, be arranged to detect a pressure on the brake block and / or wheel, which is indicative of that the parking brake has been successfully engaged.
[0077] To reduce the number of false alarms and misdetections by the control unit, it is possible to condition the parking brake engagement detection on that the rear wheel turning angle is within some predetermined parking brake angle range. No detection of parking brake engagement will then be made unless the rear wheel turning angle is close to the expected parking brake engagement angle, such as within 5-10 degrees of the expected engagement angle.
[0078] According to some aspects, when the ground sawing machine 30 is started and / or turned on, the control unit 210 is adapted to control the actuator 56 to automatically reset the rear wheel turning angle cp to a previous value that was set before the actuator 56 was controlled to pivot the rear wheel axle 46 such that at least one rear wheel 34a, 34b comes into braking engagement with the brake block 101 , 102. This means that the brake is de-activated automatically and the rear wheel axle 46 re-set to its last operational setting when the ground sawing machine 30 is turned on, for example upon activation of a start control means 204, for example in the form of a start button 204 on the sub-panel 200 or the remote-control unit 50.
[0079] According to some aspects, the control unit 210 is adapted to control the actuator 56 in dependence of activation of steering control means 205, 206 such that the wheel turning angle cp is set at a desired value. This enables an operator to set a desired position for the rear wheel axle 46 using the steering control means 205, 206, for example two buttons or a toggle switch on the sub-panel 200 or the remote-control unit 50. Apart from steering the ground sawing machine 30, this also enables an operator to turn the rear wheel axle 46 such that at least one rear wheel 34a, 34b comes into braking engagement with the brake block 101 , 102. There may be an automatic stop function that limits the possible magnitude of the turning angle cp. This also means that an operator, for example by means of the remote-control unit 50, can control the movement of the ground sawing machine 30, and in particular the ground sawing machine's movement direction D, by controlling the actuator 56 such that the ground sawing machine 30 moves in a desired movement direction D. In this way, the operator can compensate for course changes due to blade cutting resistance and other error sources by means of the remote-control unit 50.
[0080] According to some aspects, the control unit 210 is adapted to control the actuator 56 in dependence of activation of automatic course maintaining control means 201 , for example in the form of a course maintaining button 201 on the sub-panel 200 or the remote-control unit 50, such that the wheel turning angle cp is automatically set during operation such that the ground sawing machine 30 moves in a predetermined direction. In this manner, the ground sawing machine 30 can be set in an automatic mode such that a movement in a predetermined direction is maintained, compensating for course change due to blade cutting resistance and other error sources. This setting can be disengaged upon activation of disengaging control means 202, for example in the form of a disengaging button 202 on the sub-panel 200 or the remote-control unit 50.
[0081] According to some aspects, as an alternative or as a complement to controlling the movement of the ground sawing machine 30 by controlling the actuator 56, the control unit 210 is adapted to control the first motor 6a and the second motor 6b to propel the corresponding first rear wheel 34a and second rear wheel 34b independently and with either the same rotational velocity or different rotational velocities. In this manner, changing the ground sawing machine's direction D of movement can be accomplished without controlling the actuator 56 to affect the wheel turning angle cp. This can for example provide efficient turning where the rear wheels 34a, 34b even may propelled in different rotational directions.
[0082] Changing the ground sawing machine's movement direction D by controlling the rear wheels 34a, 34b to rotate with different rotational velocities can of course be combined with controlling the actuator 56 to affect the wheel turning angle cp as described previously.
[0083] In this case as well, the ground sawing machine's direction D of movement can be controlled by an operator by means of the remote-control unit 50. This enables the operator to compensate for course changes due to blade cutting resistance and other error sources by means of the remote-control unit 50.
[0084] When the rear wheel turning angle cp is configured to steer the ground sawing machine 30 along an arc, the outer wheels move on a larger radius compared to the inner wheels. If the inner and outer wheels are moved at equal speed wheel scrubbing will result. Wheel scrubbing is normally undesired since it may damage sensitive surfaces, such as non-matured concrete. Wheel scrubbing also wears the rear wheel surfaces unnecessarily much. By controlling the wheel speeds of the rear wheels of the ground sawing machine, it is possible to realize a virtual differential drive, in which the outer wheels are rotated faster compared to the inner wheels. The difference in speed can be configured based on the rear wheel turning angle cp, e.g., by using a preconfigured look-up table or an analytical function which maps rear wheel turning angle cp to wheel speed difference. To summarize, according to some aspects the control unit 210 is adapted to control the first motor 6a and the second motor 6b to propel the corresponding first rear wheel 34a and second rear wheel 34b at a rotational velocity difference corresponding to a difference in turning radii of the first rear wheel 34a and the second rear wheel 34b.
[0085] It is furthermore appreciated that the control unit 210 can use both the pivotable rear wheel axle and the independently controllable drive motors to maneuver the ground sawing machine 30. The pivotable rear wheel axle is preferably used to perform high accuracy steering during sawing, while the independent control of the drive motor speeds can be used for more aggressive steering. According to some aspects, the control unit 210 is arranged to obtain data indicative of a desired steering angle of the ground sawing machine 30, e.g., from operator input via the remote control unit 50 and to coordinate control of the rear wheel turning angle cp and a rotational velocity difference of the first rear wheel 34a and second rear wheel 34b to steer the machine 30 according to the desired steering angle. The control unit 210 may be arranged to primarily use the pivotable rear wheel axle for steering if the desired steering angle is below a threshold angle, and to use the drive motors for steering if the desired steering angle is larger than the threshold. A combination of rear axle pivoting, and speed difference can of course also be used.
[0086] According to some aspects, the control unit 210 is adapted to limit the setting of the wheel turning angle cp such that no rear wheel 34a, 34b comes into braking engagement with the brake block 101 , 102 during operation. In this manner it is avoided that a brake is activated, i.e., that at least one rear wheel 34a, 34b comes into braking engagement with the brake block 101 , 102, during operation of the ground sawing machine 30. This is of course the case for all types of operations such as manually controlled or automatically controlled operations. According to some aspects, each brake block 101 , 102 is at least partly made in metal. This enables a durable and easily manufactured brake block. For example, each brake block 101 , 102 can be made completely in metal such that a corresponding rear wheel 34a, 34b comes into braking engagement with a metal surface on the brake block 101 . Different examples will be discussed below.
[0087] According to some aspects, as shown in Figure 6A and Figure 6B, each brake block 101 , 102 has a complementary shape with respect to a wheel outer surface 634 where the brake block 101 , 102 is adapted to contact the wheel outer surface 634. In this way, a brake block engagement surface 601 is optimized to provide a large contact surface against the corresponding wheel outer surface 634.
[0088] According to some further aspects, alternatively, as shown in Figure 7A and Figure 7B, each brake block 10T has a tangential extension E with respect to a wheel outer surface 634 where the brake block 10T is adapted to contact the wheel outer surface 634. In this way, the brake blocks 101 , 102’ can be manufactured in an uncomplicated manner and have a triangular shape that is suitable for efficient storage during shipping and handling, while the brake block engagement surface 701 provides a sufficient contact surface against the corresponding wheel outer surface 634.
[0089] According to some aspects, as schematically shown in Figure 6A, Figure 6B, Figure 7A and Figure 7B, each brake block 101 , 102; 10T, 102’ comprises a brake block engagement surface 601 , 701 that is adapted to engage a wheel outer surface 634. This surface may be a metal surface of the same metal that constitutes the rest of the brake block 101 , 102, 10T, 102’ or a separate surface. According to some aspects, the brake block engagement surface 601 , 701 is constituted by a friction layer that is made in at least one of Kevlar, glass, carbon fiber and rubber. In this manner, the brake effect of a rear wheel 34a, 34b pressed against an engagement surface 601 , 701 can be enhanced.
[0090] According to some aspects, the actuator 56 is adapted to pivot the rear wheel axle 46, such that at least one rear wheel 34a, 34b comes into braking engagement with the brake block 101 , 102 by pivoting the rear wheel axle 46 such that the rear wheels 34a, 34b are turned for turning right when the ground sawing machine 30 is travelling in a movement direction D.
[0091] The present disclosure is not limited to the above but may vary freely within the scope of the appended claims. For example, at least one motor arrangement 40: 6A, 6B is electrically powered and / or at least one motor arrangement 40: 6A, 6B is constituted by a combustion engine.
[0092] With reference to Figure 1 -5, the present disclosure also relates to a ground sawing machine 30 comprising a control unit 210 and a frame 32 supported by rear wheels 34a, 34b and front wheels 36a, 36b arranged for enabling moving the ground sawing machine over a surface 38. A saw blade 2 is mounted to the frame and a first motor arrangement 40 is arranged to propel the saw blade 2 to cut against the surface 38, where the rear wheels 34a, 34b are adapted to be propelled by a second motor arrangement 6a, 6b that comprises a first motor 6a drivably connected to a first rear wheel 34a and a second motor 6b drivably connected to a second rear wheel 34b, where the rear wheels are attached to a rear wheel axle 46. A rear wheel turning angle <p is adjustable by means of an actuator 56 that is adapted to pivot the rear wheel axle 46, wherein the control unit 210 is adapted to control the first motor 6a and the second motor 6b to propel the corresponding first rear wheel 34a and second rear wheel 34b independently and with either the same rotational velocity or with different rotational velocities.
[0093] In this manner, different types of alterations can easily be made to the ground sawing machine's movement direction D.
[0094] According to some aspects, the ground sawing machine 30 comprises a remotecontrol unit 50, where the control unit 210 is adapted to control the ground sawing machine's movement direction D upon activation of control means 205, 206 comprised in the remote-control unit 50, where the control unit 210 is adapted to control the ground sawing machine's movement direction D by controlling at least one of
[0095] - the actuator 56 that is adapted to pivot the rear wheel axle 46,
[0096] - a corresponding rotational velocity of the first motor 6a and the second motor 6b. In this way, it is possible to control the movement of the ground sawing machine 30 during operation by means of the remote-control unit 50, for example an operator can compensate for course changes due to blade cutting resistance and other error sources by means of the remote-control unit 50.
[0097] According to some aspects, the control unit 210 is adapted to control the ground sawing machine's movement direction D by controlling a corresponding rotational velocity of the first motor 6a and the second motor 6b, and where upon activation of reversing control means 208 comprised in the remote-control unit 50, the control unit 210 is adapted to reverse the ground sawing machine's movement direction D by controlling the first motor 6a and the second motor 6b to rotate in different directions.
[0098] According to some aspects, upon activation of blade control means 209 comprised in the remote-control unit 50, the control unit 210 is adapted to control the first motor arrangement 40.
[0099] This means that all operations parameters of the ground sawing machine 30 can be controlled by means of the remote-control unit 50.
[0100] According to some aspects, upon activation of shift control means 21 1 comprised in the remote-control unit 50, the control unit 210 is adapted to control the ground sawing machine 30 to move to another working position by controlling at least a corresponding rotational velocity of the first motor 6a and the second motor 6b and by controlling the first motor arrangement 40 to be non-operating.
[0101] According to some aspects, there may be control means that enable input of a parallel movement distance, for example when cutting parallel tracks separated by a certain distance. The ground sawing machine 30 will then automatically move to a suitable position for cutting a new track, parallel to a previously cut track.
[0102] By controlling the amount of rotation for each rear wheel 34a, 34b and the diameter of the rear wheels 34a, 34b, the change of movement direction can be accurately controlled in a continuous manner. According to some aspects, the control unit 210 is adapted to control the ground sawing machine 30 to move to another working position by also controlling the actuator 56 that is adapted to pivot the rear wheel axle 46.
[0103] It is conceivable to have a first operating mode where the blade 2 is propelled by the first motor arrangement 40, making a cut in the ground. In the first operating mode, the ground sawing machine's movement direction D is only controlled by means of controlling the actuator 56 that is adapted to pivot the rear wheel axle 46. In a second operating mode, the first motor arrangement 40 is disengaged and the blade 2 lifted out of engagement with the ground, enabling the ground sawing machine 30 to move to another position, for example another working position or to a storage position. In the second operating mode, the ground sawing machine's movement direction D is only controlled by means of controlling the first motor 6a and the second motor 6b as described above.
[0104] In this way, smaller deviations from a present movement direction D during cutting, requiring a certain degree of precision, can be performed by means of the actuator 56 that is adapted to pivot the rear wheel axle 46. During the second operating mode, larger deviations from a present movement direction D can be desired, and this is advantageously obtained by means of controlling the first motor 6a and the second motor 6b as described above. Additionally, to provide a further degree of direction control during the second operating mode, the movement direction D is also controlled by means of controlling the actuator 56 that is adapted to pivot the rear wheel axle 46.
[0105] With reference to Figure 1 -5, the present disclosure also relates to a ground sawing machine 30 comprising a control unit 210 and a frame 32 supported by rear wheels 34a, 34b and front wheels 36a, 36b arranged for enabling moving the ground sawing machine over a surface 38, where at least one motor arrangement 40; 6A, 6B and a saw blade 2 are mounted to the frame, a first motor arrangement 40 being arranged to propel the saw blade 2 to cut against the surface 38, where the rear wheels are attached to a rear wheel axle 46, and where a rear wheel turning angle cp is adjustable by means of an actuator 56 that is adapted to pivot the rear wheel axle 46, where the ground sawing machine 30 comprises a remote-control unit 50, where the control unit 210 is adapted to control the ground sawing machine's movement direction D upon activation of steering control means 205, 206 comprised in the remote-control unit 50 by controlling the actuator 56 that is adapted to pivot the rear wheel axle 46. such that the wheel turning angle cp is set at desired value.
[0106] In this way, it is possible to control the movement of the ground sawing machine 30 during operation by means of the remote-control unit 50, for example an operator can compensate for course changes due to blade cutting resistance and other error sources by means of the remote-control unit 50.
[0107] According to some aspects, upon activation of blade control means 209 comprised in the remote-control unit 50, the control unit 210 is adapted to control the first motor arrangement 40.
[0108] This means that all operations parameters of the ground sawing machine 30 can be controlled by means of the remote-control unit 50.
[0109] According to some aspects, upon activation of control means comprised in the remotecontrol unit 50, the control unit 210 is adapted to control the ground sawing machine's movement direction D by controlling a corresponding rotational velocity of a first motor 6a and a second motor 6b.
[0110] According to some aspects, the control unit 210 is adapted to control the first motor 6a and the second motor 6b to propel the corresponding first rear wheel 34a and second rear wheel 34b independently and with either the same rotational velocity or with different rotational velocities in dependence of activation of control means comprised in the remote-control unit 50.
[0111] In this manner, different types of alterations can be made to the ground sawing machine's movement direction D by using a remote-control unit 50.
[0112] According to some aspects, upon activation of shift control means 21 1 comprised in the remote-control unit 50, the control unit 210 is adapted to control the ground sawing machine 30 to move to another working position by controlling at least a corresponding rotational velocity of the first motor 6a and the second motor 6b and by controlling the first motor arrangement 40 to be non-operating.
[0113] According to some aspects, the control unit 210 is adapted to control the ground sawing machine 30 to move to another working position by also controlling the actuator 56 that is adapted to pivot the rear wheel axle 46.
[0114] The control unit 210, together with the steering and propulsion arrangement of the ground sawing machine 30, i.e., the pivotable rear wheel axle and the independently controllable drive motors used in combination or separate, can be used to maneuver the ground sawing machine 30 in an efficient manner. The control unit 210 can maintain various complex maneuvers in memory, which can be executed in response to a control command from an operator. It is, for instance, possible to turn the ground sawing machine around to face in the opposite direction, and to perform this maneuver on a limited surface area. It is also possible to add a translational movement to the rotation, such that the ground sawing machine ends up facing the opposite direction some distance away from the start position of the maneuver. This is convenient, e.g., if it is desired to make several parallel cuts.
[0115] According to some aspects, the control unit 210 and / or the remote control unit 50 is configured to execute a sequence of maneuver commands comprising control of the actuator 56 and / or control of drive wheel speed in response to an operator command. Figure 1 1 illustrates an example maneuver comprising three commands executed in automated sequence. A first command A comprises configuring a turning radius and forwarding the machine a predetermined distance. A second command B is then issued which comprises reversing the machine at a second turning radius. A third command C then brings the machine back to the starting position but facing the opposite direction. The sequence of maneuver commands can also be configured to cause the ground sawing machine 30 to perform a translation on the surface, i.e., to move sideways a predetermined or configurable distance.
[0116] It is also possible to implement a sequence of maneuver commands that is configured to cause the ground sawing machine 30 to perform a rotation on the surface. This sequence may comprise operating the drive wheels in different directions of rotations to cause a rotation of the ground sawing machine on the surface.
[0117] The sequence of maneuver commands may comprise coordinated control of the rear wheel turning angle and the drive motors to cause the machine to steer while moving forwards and backwards. One or more such control command sequences can be stored in a memory medium of the machine. The storage medium is discussed in more detail below in connection to Figure 10.
[0118] An operator of the machine may select a given sequence of commands on the remote control device 50 to execute a desired maneuver, such as turning the machine to face in an opposite direction, moving the machine a distance sideways, or performing some other predetermined maneuver.
[0119] An operator can use the sub-panel 200 and / or the remote-control unit 50 to select which sequence of commands to perform, and also to trigger execution of the sequence, thereby controlling the operation of the ground sawing machine 30.
[0120] Figure 10 schematically illustrates, in terms of a number of functional units, the components of a control unit 50, 210, 1000 according to embodiments of the discussions herein. Processing circuitry 1010, which may be distributed over several units, is provided using any combination of one or more of a suitable central processing unit CPU, multiprocessor, microcontroller, digital signal processor DSP, etc., capable of executing software instructions stored in a computer program product, e.g., in the form of a storage medium 1030. The processing circuitry 1010 may further be provided as at least one application specific integrated circuit ASIC, or field programmable gate array FPGA.
[0121] Particularly, the processing circuitry 1010 is configured to cause the control unit 50, 210, 1000 to perform a set of operations, or steps, such as the methods discussed in connection to Figure 10 and elsewhere herein.
[0122] For example, the storage medium 1030 may store the set of operations, and the processing circuitry 1010 may be configured to retrieve the set of operations from the storage medium 1030 to cause the control unit 50, 210, 1000 to perform the set of operations. The set of operations may be provided as a set of executable instructions. Thus, the processing circuitry 1010 is thereby arranged to execute methods as herein disclosed. The control unit comprises processing circuitry 1010, an interface 1020 coupled to the processing circuitry 1010, and a memory 1030 coupled to the processing circuitry 1010, wherein the memory comprises machine readable computer program instructions that, when executed by the processing circuitry, causes the control unit to perform the methods discussed above in connection to Figure 10.
[0123] The storage medium 1030 may also comprise persistent storage, which, for example, can be any single one or combination of magnetic memory, optical memory, solid state memory or even remotely mounted memory.
[0124] The control unit 50, 210, 1000 may further comprise an interface 1020 for communications with at least one external device. As such the interface 1020 may comprise one or more transmitters and receivers, comprising analogue and digital components and a suitable number of ports for wireline or wireless communication.
[0125] The processing circuitry 1010 controls the general operation of the control unit 50, 210, 1000, e.g., by sending data and control signals to the interface 1020 and the storage medium 1030, by receiving data and reports from the interface 1020, and by retrieving data and instructions from the storage medium 1030. Other components, as well as the related functionality, of the control node are omitted in order not to obscure the concepts presented herein.
[0126] There is also disclosed a computer readable medium carrying a computer program comprising program code means for performing the methods illustrated in Figure 10 and discussed herein, when said program product is run on a computer. The computer readable medium and the code means may together form a computer program product.
Claims
CLAIMS1 . A ground sawing machine (30) comprising a control unit (210) and a frame (32) supported by rear wheels (34a, 34b) and front wheels (36a, 36b) arranged for enabling moving the ground sawing machine over a surface (38), where at least one motor arrangement (40; 6A, 6B) and a saw blade (2) are mounted to the frame, a first motor arrangement (40) being arranged to propel the saw blade (2) to cut against the surface (38), where a rear wheel turning angle (cp) is adjustable by means of an actuator (56) that is adapted to pivot a rear wheel axle (46), wherein the ground sawing machine (30) comprises at least one brake block (101 , 102) that is fixed or fixedly mounted relative the frame (32), where the actuator (56) is adapted to pivot the rear wheel axle (46) such that at least one rear wheel (34a, 34b) comes into braking engagement with the brake block (101 , 102).
2. The ground sawing machine (30) according to claim 1 , wherein the actuator (56) is an electrically controlled actuator.
3. The ground sawing machine (30) according to claim 1 or 2, wherein the control unit (210) is adapted to control the actuator (56) in dependence of activation of control means (203, 204, 205, 206).
4. The ground sawing machine (30) according to any one of the previous claims, wherein the control unit (210) is adapted to control the actuator (56) in dependence of activation of brake control means (207), where the control unit (210) is adapted to control the actuator (56) to automatically pivot the rear wheel axle (46) such that at least one rear wheel (34a, 34b) comes into braking engagement with the brake block (101 , 102) upon activation of the brake control means (207).
5. The ground sawing machine (30) according to any one of the previous claims, wherein the control unit (210) is adapted to control the actuator (56) to automatically pivot the rear wheel axle (46), such that at least one rear wheel (34a, 34b) comes into braking engagement with the brake block (101 , 102) when the ground sawing machine (30) is stopped and / or turned off.
6. The ground sawing machine (30) according to any one of the previous claims, wherein, when the ground sawing machine (30) is started and / or turned on, the control unit (210) is adapted to control the actuator (56) to automatically reset the rear wheel turning angle (cp) to a previous value that was set before the actuator (56) was controlled to pivot the rear wheel axle (46) such that at least one rear wheel (34a, 34b) comes into braking engagement with the brake block (101 , 102).
7. The ground sawing machine (30) according to any one of the previous claims, wherein the control unit (210) is adapted to control the actuator (56) in dependence of activation of steering control means (205, 206) such that the wheel turning angle (cp) is set at desired value.
8. The ground sawing machine (30) according to any one of the previous claims, wherein the control unit (210) is adapted to control the actuator (56) in dependence of activation of automatic course maintaining control means (201 ) such that the wheel turning angle (cp) is automatically set during operation such that the ground sawing machine (30) moves in a predetermined direction.
9. The ground sawing machine (30) according to any one of the claims 7 or 8, wherein the control unit (210) is adapted to limit the setting of the wheel turning angle (cp) such that no wheel (34a, 34b) comes into braking engagement with the brake block (101 , 102) during operation.
10. The ground sawing machine (30) according to any one of the previous claims, wherein the actuator (56) is an at least partly manually controlled actuator.
11. The ground sawing machine (30) according to claim 10, wherein the actuator (56) is displaced by manually turning a nut or a threaded rod.
12. The ground sawing machine (30) according to any one of the previous claims, wherein said brake block (101 , 102) at least partly is made in metal.
13. The ground sawing machine (30) according to any one of the previous claims, wherein said brake block (101 , 102) comprises a brake block engagement surface (601 ) that is adapted to engage a wheel outer surface (634).
14. The ground sawing machine (30) according to claim 13, wherein the brake block engagement surface (601 ) is constituted by a friction layer that is made in at least one of Kevlar, glass, carbon fiber and rubber.
15. The ground sawing machine (30) according to any one of the previous claims, wherein each brake block (101 , 102) is releasably mounted to a brake block holder (103, 104) that is attached to the frame (32).
16. The ground sawing machine (30) according to any one of the previous claims, wherein each brake block (101 , 102) has a complementary shape with respect to a wheel outer surface (634) where the brake block (101 , 102) is adapted to contact the wheel outer surface (634).
17. The ground sawing machine (30) according to any one of the claims 1 -15, wherein each brake block (101 ’) has a tangential extension (E) with respect to a wheel outer surface (634) where the brake block (101 ’) is adapted to contact the wheel outer surface (634).
18. The ground sawing machine (30) according to any one of the previous claims, wherein the rear wheels (34a, 34b) are adapted to be propelled by a second motor arrangement (6a, 6b).
19. The ground sawing machine (30) according to any one of the previous claims, wherein the motor arrangement comprises a first electric or hydraulic motor (6a) drivably connected to a first rear wheel (34a) and a second electric or hydraulic motor (6b) drivably connected to a second rear wheel (34b).
20. The ground sawing machine (30) according to claim 19, wherein the control unit (210) is adapted to control the first motor (6a) and the second motor (6b) to propel the corresponding first rear wheel (34a) and second rear wheel (34b)independently and with either the same rotational velocity or with different rotational velocities.21 . The ground sawing machine (30) according to any one of the previous claims, wherein the saw blade (2) is a diamond saw blade.
22. The ground sawing machine (30) according to any one of the previous claims, wherein the actuator (56) is adapted to pivot the rear wheel axle (46), such that at least one rear wheel (34a, 34b) comes into braking engagement with the brake block (101 , 102) by pivoting the rear wheel axle (46) such that the rear wheels (34a, 34b) are turned for turning right when the ground sawing machine (30) is travelling in a movement direction (D).
23. The ground sawing machine (30) according to any one of the previous claims, wherein the actuator (56A) is a linear actuator that comprises a threaded rod (700) that engages inner threads of a nut part (702), where the threaded rod (700) is displaced by means of rotation of the nut part (702).
24. The ground sawing machine (30) according to any one of the claims 1 -22, wherein the actuator (56B) is a linear actuator that comprises a threaded rod (706) that engages inner threads of a nut part (704), where the nut part (704) is displaced by means of rotation of the threaded rod (706).
25. The ground sawing machine (30) according to any one of the previous claims, wherein the rear wheels (34a, 34b) have a common wheel rotation axis (35), where the actuator (56) is adapted to pivot the rear wheel axle (46) about a pivot axis (37) that is perpendicular to the wheel rotation axis (35).
26. The ground sawing machine (30) according to any one of the previous claims, where the control unit (210) is configured to detect that at least one rear wheel (34a, 34b) is in braking engagement with the brake block (101 , 102).
27. The ground sawing machine (30) according to claim 26, where the control unit (210) is configured to detect that the at least one rear wheel (34a, 34b) is in brakingengagement with the brake block (101 , 102) at least in part by monitoring a current or power consumption of the actuator (56).
28. The ground sawing machine (30) according to claim 26 or 27, where the control unit (210) is configured to detect that the at least one rear wheel (34a, 34b) is in braking engagement with the brake block (101 , 102) at least in part by monitoring an output signal from a position sensor arranged in connection to the at least one rear wheel (34a, 34b), the brake block (101 , 102), and / or the rear wheel axle (46).
29. The ground sawing machine (30) according to any of claims 26-28, where the control unit (210) is configured to detect that the at least one rear wheel (34a, 34b) is in braking engagement with the brake block (101 , 102) at least in part by monitoring an output signal from a pressure sensor arranged in connection to the at least one rear wheel (34a, 34b) and / or the brake block (101 , 102).
30. The ground sawing machine (30) according to any of claims 26-29, where the control unit (210) is configured to detect that the at least one rear wheel (34a, 34b) is in braking engagement with the brake block (101 , 102) conditioned on that the rear wheel axle (46) has a rear wheel turning angle (cp) within a parking brake angle range.31 . A ground sawing machine (30) comprising a control unit (210) and a frame (32) supported by rear wheels (34a, 34b) and front wheels (36a, 36b) arranged for enabling moving the ground sawing machine over a surface (38), where a saw blade (2) is mounted to the frame and a first motor arrangement (40) is arranged to propel the saw blade (2) to cut against the surface (38), where the rear wheels (34a, 34b) are adapted to be propelled by a second motor arrangement (6a, 6b) that comprises a first motor (6a) drivably connected to a first rear wheel (34a) and a second motor (6b) drivably connected to a second rear wheel (34b), where the rear wheels are attached to a rear wheel axle (46), and where a rear wheel turning angle (cp) is adjustable by means of an actuator (56) that is adapted to pivot the rear wheel axle (46), wherein the control unit (210) is adapted to control the first motor (6a) and the second motor (6b) to propel the corresponding first rear wheel (34a) and second rear wheel (34b) independently and with either the same rotational velocity or with different rotational velocities.
32. The ground sawing machine (30) according to claim 31 , wherein the ground sawing machine (30) comprises a remote-control unit (50), where the control unit (210) is adapted to control the ground sawing machine's movement direction (D) upon activation of control means (205, 206) comprised in the remote-control unit (50), where the control unit (210) is adapted to control the ground sawing machine's movement direction (D) by controlling at least one of- the actuator (56) that is adapted to pivot the rear wheel axle (46),- a corresponding rotational velocity of the first motor (6a) and the second motor (6b).
33. The ground sawing machine (30) according to claim 32, wherein the control unit (210) is adapted to control the ground sawing machine's movement direction (D) by controlling a corresponding rotational velocity of the first motor (6a) and the second motor (6b), and where upon activation of reversing control means (208) comprised in the remote-control unit (50), the control unit (210) is adapted to reverse the ground sawing machine's movement direction (D) by controlling the first motor (6a) and the second motor (6b) to rotate in different directions.
34. The ground sawing machine (30) according to any one of the claims 32 or33, wherein, upon activation of blade control means (209) comprised in the remotecontrol unit (50), the control unit (210) is adapted to control the first motor arrangement (40).
35. The ground sawing machine (30) according to anyone of the claims 31 -34, wherein, upon activation of shift control means (210) comprised in the remotecontrol unit (50), the control unit (210) is adapted to control the ground sawing machine (30) to move to another working position by controlling at least a corresponding rotational velocity of the first motor (6a) and the second motor (6b) and by controlling the first motor arrangement (40) to be non-operating.
36. The ground sawing machine (30) according to claim 35, wherein the control unit (210) is adapted to control the ground sawing machine (30) to move toanother working position by also controlling the actuator (56) that is adapted to pivot the rear wheel axle (46).
37. The ground sawing machine (30) according to any of claims 31 -36, where the control unit (210) is adapted to control the first motor (6a) and the second motor (6b) to propel the corresponding first rear wheel (34a) and second rear wheel (34b) at a rotational velocity difference corresponding to a difference in turning radii of the first rear wheel (34a) and the second rear wheel (34b).
38. The ground sawing machine (30) according to any of claims 31 -37, where the control unit (210) is arranged to obtain data indicative of a desired steering angle of the ground sawing machine (30) and to coordinate control of the rear wheel turning angle (cp) and a rotational velocity difference of the first rear wheel (34a) and second rear wheel (34b) to steer the machine (30) according to the desired steering angle.
39. A ground sawing machine (30) comprising a control unit (210) and a frame (32) supported by rear wheels (34a, 34b) and front wheels (36a, 36b) arranged for enabling moving the ground sawing machine over a surface (38), where at least one motor arrangement (40; 6A, 6B) and a saw blade (2) are mounted to the frame, a first motor arrangement (40) being arranged to propel the saw blade (2) to cut against the surface (38), where the rear wheels are attached to a rear wheel axle (46), and where a rear wheel turning angle (cp) is adjustable by means of an actuator (56) that is adapted to pivot the rear wheel axle (46), where the ground sawing machine (30) comprises a remote-control unit (50), where the control unit (210) is adapted to control the ground sawing machine's movement direction (D) upon activation of steering control means (205, 206) comprised in the remote-control unit (50) by controlling the actuator (56) that is adapted to pivot the rear wheel axle (46), such that the wheel turning angle (cp) is set at a desired value.
40. The ground sawing machine (30) according to claim 39, wherein, upon activation of blade control means (209) comprised in the remote-control unit (50), the control unit (210) is adapted to control the first motor arrangement (40).41 . The ground sawing machine (30) according to any one of the claims 39 or 40, wherein, upon activation of control means comprised in the remote-control unit (50), the control unit (210) is adapted to control the ground sawing machine's movement direction (D) by controlling a corresponding rotational velocity of a first motor (6a) and a second motor (6b).
42. The ground sawing machine (30) according to claim 41 , wherein the control unit (210) is adapted to control the first motor (6a) and the second motor (6b) to propel the corresponding first rear wheel (34a) and second rear wheel (34b) independently and with either the same rotational velocity or with different rotational velocities in dependence of activation of control means comprised in the remotecontrol unit (50).
43. The ground sawing machine (30) according to anyone of the claims 41 or 42, wherein, upon activation of shift control means (210) comprised in the remotecontrol unit (50), the control unit (210) is adapted to control the ground sawing machine (30) to move to another working position by controlling at least a corresponding rotational velocity of the first motor (6a) and the second motor (6b) and by controlling the first motor arrangement (40) to be non-operating.
44. The ground sawing machine (30) according to claim 43, wherein the control unit (210) is adapted to control the ground sawing machine (30) to move to another working position by also controlling the actuator (56) that is adapted to pivot the rear wheel axle (46).
45. The ground sawing machine (30) according to anyone of the claims 39- 44, where the control unit (210) and / or the remote control unit (50) is configured to execute an automated sequence of maneuver commands comprising control of the actuator (56) and / or control of drive wheel speed in response to an operator command.
46. The ground sawing machine (30) according to claim 45, where the sequence of maneuver commands is configured to cause the ground sawing machine (30) to perform a rotation on the surface.M . The ground sawing machine (30) according to claim 45, where the sequence of maneuver commands is configured to cause the ground sawing machine (30) to perform a translation on the surface.
48. A ground sawing machine (30) comprising a control unit (210) and a frame(32) supported by rear wheels (34a, 34b) and front wheels (36a, 36b) arranged for enabling moving the ground sawing machine over a surface (38), where at least one motor arrangement (40; 6A, 6B) and a saw blade (2) are mounted to the frame, a first motor arrangement (40) being arranged to propel the saw blade (2) to cut against the surface (38), where a front wheel turning angle is adjustable by means of an actuator that is adapted to pivot a front wheel axle, wherein the ground sawing machine (30) comprises at least one brake block that is fixed or fixedly mounted relative the frame (32), where the actuator is adapted to pivot the front wheel axle such that at least one front wheel (36a, 36b) comes into braking engagement with the brake block.