Abstract
The invention relates to a device for cutting concrete piles. The device having a frame, gripping means connected to the frame and including at least two opposing gripping parts, which are movable at least closer to each other to form a closing grip around a pile and further away from each other to release the pile from the closing grip, and sawing means, which are arranged to perform a back and forth sawing movement on the two opposite sides of the pile moving along a horizontal guide rail attached to the frame and which is further arranged to turn towards the pile to be sawed and back around their rotational axis. The invention further relates to computer program means suitable for controlling a device according to the invention to perform a desired sawing profile in the concrete pile.
Claims
1. A device for cutting concrete piles, comprising a frame, gripping means connected to the frame and comprising at least two opposing gripping parts, which are movable at least closer to each other to form a closing grip around a pile and further away from each other to release a pile from the closing grip, and sawing means, which, when using the device, are to be taken on the two opposite sides of the pile to perform a back and forth sawing movement moving along a horizontal guide rail attached to the frame and which are further arranged to turn towards the pile to be sawed and back around their rotational axis wherein the device comprises a turning mechanism, an angle sensor arranged in the end of the rotational axis for measuring the angle of rotation of the sawing means and elements for defining the location of the sawing means on the guide rail and control elements for controlling the sawing means on the basis of the signals from the angle sensor and the elements defining the location of the sawing means to perform a de-sired sawing profile in the concrete pile to be cut.
2. The device according to claim 1, wherein the device comprises an inductive sensor for detecting the steel rebars in the pile.
3. The device according to claim 1, wherein the device comprises an adjustable friction brake arranged in the turning mechanism.
4. A computer program containing a computer program for controlling a device according to claim 1 to perform a desired sawing profile in the concrete pile to be cut.
5. The device according to claim 2, wherein the device comprises an adjustable friction brake arranged in the turning mechanism.
6. The computer program containing a computer program for controlling a device according to claim 2 to perform a desired sawing profile in the concrete pile to be cut.
7. The computer program containing a computer program for controlling a device according to claim 3 to perform a desired sawing profile in the concrete pile to be cut.
Description
LIST OF FIGURES
[0030] FIG. 1 shows schematically the cutting profile of a concrete pile cut according to a cutting method according to one embodiment and performed by a device according to the invention;
[0031] FIG. 2 shows schematically the cutting profile of a concrete pile cut according to a cutting method according to another embodiment and performed by a device according to the invention;
[0032] FIG. 3 shows a perspective view of one embodiment of a device according to the invention;
[0033] FIGS. 4a-4c show one embodiment of the turning mechanism of a device according to the invention.
DETAILED DESCRIPTION OF THE FIGS.
[0034] FIGS. 1-2 show the cutting stages of the concrete of a concrete pile used in a cutting method performed by a device according to the invention.
[0035] By using a device according to the invention, it is best possible to perform demolition cutting of the steel rebars in the rectangular concrete piles, as shown in FIGS. 1-3. The steel rebars 22 extending longitudinally in the rectangular piles 23 are generally arranged in the corners, wherein in each corner of a concrete pile 23 is located one steel rebar 22. Depending on the thickness of the concrete pile 23, which is typically 20-45 cm, to the middle between the steel rebars remains thus approximately 10-35 cm free space, which can be sawed.
[0036] Concrete is often cut by a diamond wheel or diamond chain saw. The aim is always to saw the concrete as deeply as possible to cut the pile, however, without damaging the steel rebars.
[0037] FIG. 1 shows schematically a concrete pile 23, which the gripping means 2 hold in a closing grip. The gripping means 2 hold onto the pile 23 during the sawing and prevent its uncontrolled falling. In a cutting method performed by a device according to the invention, the pile 23 is sawed from both sides of the pile as deeply as possible without striking the steel rebars 22. FIG. 1 shows the cutting surface 21 achieved by sawing. In this example, the pile 23 is sawed in a back and forth sawing movement along the edge of the pile and between the steel rebars 22, in which the diamond cutting edge of the sawing means 3 is able to progress a little deeper. Preferably, the device used has two sawing means arranged opposite each other, wherein it is possible to saw the pile from both sides simultaneously. If necessary, the device can also be programmed to saw one side at a time. The device can also have more than two sawing means.
[0038] FIG. 2 shows the cutting surface 21 achieved in the pile 23 when, after the sawing shown in FIG. 1, the sawing means are turned 90 around the pile, after which is performed the same kind of cutting as in FIG. 1. The sawing means 3 can be arranged 90 turnable around the pile, the frame of the cutting device being in its place, wherein the gripping means 2 do not need to release their grip during the turning. However, it is often necessary to temporarily release at least one gripping means 2, after which the cutting device can be turned and thereafter again take hold of the pile with the gripping means 2.
[0039] FIG. 3 shows a perspective view of one embodiment of a cutting device according to the invention. The figure shows the opposite side of the device, which has movable gripping means 2 and sawing means 3. Preferably, the opposite side of the device 1 is arranged identically as a mirror image. The sawing means 3 and its moving mechanisms are herein attached to the gripping means 2. The sawing means 3 can be attached pivotable and/or movable also to the frame of the cutting device. The sawing means 3 of the figure are arranged to move in the longitudinal direction of the gripping means 2 and thus along the guide rail 6 along the edges of the concrete pile. The saw carriage 5 can be moved along the guide rail 6, for example, by means of a trapezoidal screw, which is moved by the drive motor 7. According to one embodiment, the drive motor 7 can be a servo motor, wherein it is possible to precisely control the location of the sawing means in the longitudinal direction of the gripping means 2. In connection with the trapezoidal screw can also be arranged a separate detector (not shown), which precisely indicates the location of the saw carriage. The sawing means 3 are arranged to be turned towards the pile to be sawed and away from it by a turning mechanism 8, and the rotating sawing movement of the sawing means is created by a drive motor 11. In both ends of the rotational axis of the turning mechanism 8 of the sawing means is fitted an angle sensor 9, which gives a signal regarding the angle of rotation of the saw blade. The automation system can by means of the angle of rotation, the location of the saw carriage 5 and the structural dimensions precisely calculate the location of the cutting edge of the sawing means 3 in the concrete pile 23, wherein it can guide the sawing means 3 along a desired sawing path in the pile. The cutting device 1 is further provided with at least one inductive sensor 10 to detect the steel rebars in the concrete, wherein it is possible to stop the movement of the sawing means 3 of the device 1, when the sensor 10 comes too close to a steel rebar.
[0040] Preferably, the majority of the demolition cutting of the steel rebars of the concrete pile is automated, for example, using logic control. According to one embodiment, the machine operator performs cutting of the pile at a height, which corresponds to the desired embedded length of the pile 23 added to the desired height of the steel rebars 22 to be left exposed, and after this moves the cutting device 1 to the desired cutting height of the concrete. It may be necessary for the user to feed the dimensions of the concrete pile 23 into the control system, or the cutting device 1 may have sensors for defining the distance between the gripping means 2 and thus the thickness of the pile 23. Preferably, after this, the user can start the automatic program for demolition cutting of steel rebars, which performs the horizontal sawing according to the method and, if necessary, additional sawings for removal of the concrete. If necessary, the user controls in each of the stages the gripping onto the piles 23 by the gripping means 2, the releasing off by the gripping means 2 and the movement and/or turning of the cutting device 1 to a desired site. The user can also control the lifting away from the pile 23 of the concrete pieces to be removed.
[0041] FIGS. 4a-4c show in greater detail the turning mechanism 8 of the sawing means 3 according to one embodiment. The figures show the axis 13 of the turning mechanism 8, onto which the sawing means 3 are connected. The figures further show the angle sensor 9 to measure the angle of rotation of the axis 13 and thus of the sawing means 3. The magnetic screw 12 of the angle sensor is connected to the end of the axis 13 and the sensor 9 itself is attached onto the disc 11.
[0042] The turning mechanism of FIGS. 4a-4c is provided with a pressure element, which presses the sawing means 3 towards the pile to be sawed. Preferably, this pressure element is a flexible pressure element in order that the sawing means is able to conform to the momentary great compressive forces, to which they are subjected in the direction deviating from the longitudinal direction of the gripping means 2, for example, when the saw blade strikes harder points in the concrete, such as stones. The flexible pressure element is preferably implemented as a torsion spring connected to the axis of the turning mechanism. The turning mechanism of the sawing means 3 is preferably further provided with a moving element, which performs the moving of the sawing means 3 and which is capable of moving the sawing means 3 against the force of the pressure element back into the start position. This moving element can be, for example, a hydraulic cylinder.
[0043] The disadvantage of the flexibility of the turning mechanism is that it can create a bouncing of the blade in the concrete, which decreases the efficiency of sawing and creates both uneven cutting result and wearing of the blade. This occurs, in particular, when using a spring having a too weak, i.e. a too low spring force in relation to the material to be cut.
[0044] The turning mechanism 8 of the sawing means 3 of a cutting device according to the invention is, for this reason, in addition to a conforming spring mechanism, also provided with an adjustable friction brake, which resists the flexible movement of the axis 13 and the therein connected sawing means 3. In the embodiment shown in FIGS. 4a-4c, the friction brake comprises a metal plate 17 attached to the end of the rotating rotational axis 13, to which metal plate is combined, for example, by gluing, a friction plate 15. The plates 17 and 15 are attached with a magnetic screw 12 to the end of the axis 13 turning along with it. The metal plate 17 is preferably also attached in a form-fitted manner to the end of the axis 13 using a non-circular opening in the metal plate and by making bevels in the end of the axis, which achieve form locking. On top of the friction plate 15 is fitted at least one compression plate 14, which is compressed by the adjustment springs 16 against the plate 15, thus braking by friction the movement of the plate 15 and the axis connected therein. By adjusting the adjustment screws 16 provided with springs, which can be, for example, two or four, it is possible to set the magnitude of the braking force of the friction brake and then how stiff or flexible the flexibility of the turning mechanism is. The adjustment screws 16 attach the plate 14 in a non-rotational manner to the frame of the turning mechanism 18. By means of the locking pegs 20, the plate 14 can be locked in place in relation to the frame of the turning mechanism without any gap, even if there were to be a slight clearance at the screw connections. The friction brake can also be implemented in a different manner than what is presented. The friction brake prevents the bouncing of the blade during sawing and, at the same time, allows a flexible feature, which can be adjusted as suitable, for example, according to the material to be cut.
[0045] The device further has a protective casing (not shown in the drawings), to the bottom of which, below the saw blade is arranged a discharge opening, in connection with which is arranged a part guiding away the sawing dust.
