EP1209290A1

EP1209290A1 - Paving device

Info

Publication number: EP1209290A1
Application number: EP01870255A
Authority: EP
Inventors: August Laurijssen
Original assignee: Laurijssen Bvba
Current assignee: Laurijssen Bvba
Priority date: 2000-11-22
Filing date: 2001-11-22
Publication date: 2002-05-29
Also published as: BE1013850A5

Abstract

1. A device for laying paving bricks, comprising a gripper for gripping, transporting and laying a paving brick layer, the gripper on at least a first side (2; 41) comprising at least one movable clamping element (3; 45; 47), each movable clamping element (3; 45; 47) being movable between an open position removed from the paving brick layer and a clamping position for clamping the paving brick layer against a fixed clamping element (4; 46; 48) at a second, opposite side (5 ; 42) of the gripper (1; 40), the gripper (1; 40) being provided with means (16; 55) for contacting an upper surface of the paving brick layer, characterized in that these means (16; 55) are rotatably positioned in the gripper (1; 40) to allow a positioning of the gripper before clamping the paving brick layer and while these means (16; 55) are contacting the upper surface of the paving brick layer.

Description

This invention relates to a paving device according to the preamble of the first claim.
A paving device is for example known from WO-A-85/04435. This document describes a device comprising a motor vehicle provided with a holder for holding a gripper for gripping, transporting and laying a paving brick layer. On a first side the gripper comprises a multitude of movable clamping elements. On a second side, opposite the first side, the gripper comprises a multitude of fixed clamping elements. Each fixed clamping element is located opposite a movable clamping element. The movable clamping elements are movable between an open position removed from the paving brick layer and a clamping position in which the paving bricks are clamped between the fixed clamping elements and the movable clamping elements. The movable and fixed clamping elements are connected to each other via separate supporting systems, resting upon the upper surface of the paving brick layer before being fixed.
A paving device is further known from EP-A-0.035.159. The gripper of the device described herein comprises at a first side a movable clamping element and at a second, opposite side a fixed clamping element. The gripper is further provided with means for contacting the upper surface of the paving brick layer. These means are mounted adjustable in height direction of the gripper, such that the gripper can be adjusted to the height of the paving brick layer that has to be picked up.
The devices described in WO-A-85/04435 and EP-A-0.035.159 however have the disadvantage of a great risk that the paving bricks of the layer are moved apart during positioning of the gripper with respect to the layer before gripping.
It is an aim of this invention to provide a paving device with which the risk that paving bricks are moved apart can be limited.
This aim is achieved according to the invention with a device showing the technical characteristics of the characterising part of the first claim.
In the device according of the invention, the means for contacting the upper surface of the paving brick layer are rotatably mounted in the gripper. These rotatable means are contacting the upper surface of the paving brick layer when the gripper is positioned on top of the paving brick layer before gripping the layer. To obtain a good clamping of the paving bricks, it is desirable to suitably position the gripper at that moment, such that the clamping elements are substantially parallel to the side walls of the paving brick layer. By the rotatability of these contacting means, a substantially frictionless positioning of the gripper can be achieved, and thus a spreading apart of the paving bricks as a consequence of the contact with these contacting means can be prevented.
As the risk of the spreading apart of the paving bricks can be limited, it is possible to improve the clamping of the paving bricks in between the clamping elements, such that the risk of the falling of a paving brick out of the layer during transport with the gripper can be limited. A further consequence is that the paving bricks can be kept in the desired relative position to each other in a better way, such that the paving bricks after having been laid down, are already substantially in the desired position and that the skilled person needs less time on correctly positioning the paving bricks. As a consequence hereof, a higher paving speed can be achieved with the device of the present invention.
In a preferred embodiment of the device of the present invention, the rotatable contacting means are formed by at least three wheels which are on the one hand rotatable about an axis substantially parallel to the upper surface of the paving brick layer and on the other hand rotatable about an axis substantially perpendicular to the upper surface of the paving brick layer. These double rotatable wheels form a simple construction to obtain the rotatable means which contact the upper surface of the upper paving brick layer. They ensure that the gripper can roll on the upper surface of the paving brick layer in each direction, substantially without spreading apart the paving bricks with respect to each other. The at least three wheels are preferably provided in the gripper at distances from each other such that the gripper is able to rest substantially stable upon the paving brick layer. The rotatable means may however also be constructed in any other way known to the person skilled in the art.
In the device according to the invention, the gripper preferably comprises a fixed positioning element on a third side substantially perpendicular to the first side. This fixed positioning element extends over substantially the entire length of the third side and is provided to be brought against a side wall of the paving brick layer. This fixed positioning element forms an aid for positioning the gripper with respect to the paving brick layer before gripping them. By providing the fixed positioning element, it can be made sure that the paving bricks stay in their position when transporting them by means of the gripper.
The gripper preferably further comprises a movable positioning element on a fourth side opposite the third side. This movable positioning element extends over substantially the entire length of the fourth side of the gripper and is movable between an open position removed from the paving brick layer and a contact position in which the paving brick layer is positioned between the fixed and the movable positioning elements. In this way, the gripper can be positioned with respect to the paving brick layer in a simple way by bringing the movable positioning element against the paving bricks. A deviation in the direction between the positioning elements and the side walls of the paving brick layer can be compensated since the gripper can roll on the upper surface. In the same way as the fixed positioning element, the movable positioning element can make sure that the paving bricks stay together.
Preferably, the movable clamping elements on the first side of the gripper are rotatably mounted around a substantially cylindrical axle. So the movable clamping elements on the first side of the gripper are preferably not each mounted on a separate supporting element as in the known device, but on a substantially cylindrical axle, which constitutes a common supporting element for all the movable clamping elements on the first side. In this way, only one supporting element is required for mounting the movable clamping elements on the first side of the gripper. Furthermore, each movable clamping element is loose from the opposite fixed clamping element. The absence of a connection can leadto a reduction in the weight of the device.
As the gripper in the device of the invention has a smaller weight, the motor vehicle for operating the gripper can also have a smaller weight. In the device known from the prior art, a motor vehicle with a larger weight is required, as the weight of the motor vehicle has to form a counterweight for the weight of the gripper. As a result, the overall weight of the motor vehicle and the gripper in the prior art device is much larger than in the device of the invention. A consequence of this is that there is less risk with the device of the invention that paving bricks which have already been laid are moved or subside when the motor vehicle rides over them.
For the movement from the open position to the clamping position and back, the device of the invention is preferably provided with a hydraulic drive with hydraulic cylinders, one per movable clamping element. The movement can however also be obtained by means of a mechanical or pneumatic drive, or in any other way known to the person skilled in the art.
In a first preferred embodiment of the device of the invention, each movable clamping element on the first side of the gripper comprises a foot which is provided to be brought against the side wall of the paving brick layer and which extends over substantially the length of at least two paving bricks. By means of this foot, each movable clamping element is provided to clamp at least two rows of the paving brick layer which extend between the movable clamping element and the fixed clamping element. Providing such a foot has the advantage that the number of movable clamping elements on the gripper, and as a result also the number of hydraulic cylinders, can be reduced. This may lead to a further reduction of the weight of the gripper.
The gripper in the first embodiment of the device of the invention preferably comprises one fixed clamping element on the second side, which extends over substantially the entire length of the second side of the gripper. Providing only one, oblong fixed clamping element has the advantage that the weight of the gripper can be further reduced, as no separate supporting elements need to be provided on the gripper for mounting a multitude of fixed clamping elements, as is the case in the device known from the prior art. Furthermore, this may lead to a better clamping of the paving brick layer, as the fixed clamping element extends over substantially the entire length of the second side, by which the presence of openings between a multitude of separate fixed clamping elements is avoided.
In order to ensure that the entire paving brick layer can be sufficiently clamped between the movable clamping elements on the first side and the fixed clamping element on the second side of the gripper, the fixed clamping element is preferably provided with means for overcoming irregularities on the side wall of the paving brick layer with which it comes into contact. These means for overcoming irregularities are preferably formed by a multitude of resilient elements, preferably plates that are mounted next to each other in longitudinal direction of the fixed clamping element on the second side of the gripper. As these plates are resilient, they will bend when they come into contact with the side wall of the paving brick layer. A resilient plate which comes into contact with an protruding irregularity on the side wall of the paving brick layer will bend more than an other plate, so that all plates are able to come into contact with the side wall of the paving brick layer. The resiliency also makes sure that the plates substantially return to their original position upon releasing the paving brick layer. The means for overcoming irregularities may however also be formed by a rubber strip over the length of the fixed clamping element, or by any other means known to the person skilled in the art.
The embodiments of the device according to the invention described above are suitable for gripping, transporting and laying a paving brick layer with a substantially rectangular or square shape, the paving bricks being arranged in rows and in columns. So far, no device is known with which paving bricks can be laid in the "zigzag" or "herringbone" pattern, which is known to the person skilled in the art. The difficulty in laying paving bricks in this pattern is that they cannot be laid in a substantially rectangular shape, without spaces remaining open along the edge of the rectangle. When such paving brick layer in such a pattern would be gripped with a device known in the art, not all the paving bricks would be clamped in the gripper because of the open spaces in the layer. As a result, the paving bricks located next to an open space along the edge of the rectangle, would fall out of the gripper. In a particular embodiment of the device of the invention, this is solved by providing means for filling open spaces between paving bricks of a paving brick layer with a herringbone pattern. These means are preferably wheels, which extend in a direction substantially perpendicular to the first side of the gripper and have a diameter substantially equal to the width of the open spaces. When two paving brick layers with the herringbone pattern are laid next to each other with the above described device according to the invention, one or more open spaces remain, each being able to fit one paving brick. The person skilled in the art can afterwards fill these open spaces by placing a paving brick in them.
A second preferred embodiment of the invention is designed for laying paving bricks in the "stretcher" pattern, which is known to the person skilled in the art. In the stretcher pattern, the paving bricks in a first row are displaced over half the length of a paving brick with respect to the paving bricks in a second row adjacent the first row. In laying paving bricks in this pattern it is conventional that the paving bricks are initially placed in a rectangular layer, as they are stacked and packed in this way. Therefore, in laying paving bricks in the stretcher pattern, it is required that the device is provided to displace the paving bricks from the rectangular pattern to the stretcher pattern. In the second embodiment of the device according to the invention, this is achieved as follows. On the first side the gripper comprises first movable clamping elements alternating with first fixed clamping elements and on the second side opposite the first side the gripper comprises second movable clamping elements alternating with second fixed clamping elements. The clamping elements are mounted in such a way that the second fixed clamping elements oppose the first movable clamping elements and that the second movable clamping elements oppose the first fixed clamping elements. Furthermore, the fixed and movable clamping elements oppose each other in such a way, that upon clamping a first row of paving bricks of the paving brick layer is displaced over a predetermined length with respect to a second row of paving bricks adjacent the first row. This means that, viewed in longitudinal direction of the rows of paving bricks, the first movable clamping elements in the clamping position are located at a predetermined distance from the first fixed clamping elements. Correspondingly, viewed in longitudinal direction of the rows of paving bricks, the second movable clamping elements are located at a predetermined distance from the second fixed clamping elements. This predetermined distance is preferably chosen such that it equals half the length of a paving brick, but it may also have any other length.
In this second embodiment the rotatable means, provided to allow the positioning of the gripper with respect to the paving brick layer, have an additional function. They allow the paving bricks to be displaced with respect to each other to the stretcher pattern, substantially without that the contact with the gripper impedes herewith. Consequently, the rotatable means aid in preventing that the paving bricks spread apart when they are displaced with respect to each other. In this second embodiment, also the fixed and the movable positioning element can prevent that the paving bricks, when they are displaced with respect to each other under influence of the movable clamping elements, undergo a sidelong displacement.
In the second embodiment of the device according to the invention described above, the second movable clamping elements on the second side of the gripper are preferably rotatably mounted on a second substantially cylindrical axle, in correspondence with the first movable clamping elements on the first side of the gripper. This has the advantage that the weight of the device according to the second embodiment can be limited.
In all the embodiments of the device according to the invention described above, the gripper is preferably provided with means for adjusting the distance between each movable clamping element in the clamping position and the opposing fixed clamping element. Providing these means has the advantage that the gripper can be adjusted for gripping, transporting and laying paving brick layers in different sizes.
The gripper is preferably also provided with means for adjusting the distance between the fixed positioning element and the movable positioning element in the contact position to the measures of the paving brick layer.
The means for contacting the upper surface of the paving brick layer are preferably adjustable in height direction. In this way it can be made sure that the gripper takes a suitable position above the paving brick layer in consideration of the height of the paving bricks , before gripping the layer.
The device according to the invention will be further elucidated by means of the following description and the appended figures.
Figure 1 shows a first preferred embodiment of the device according to the invention.
Figure 2 shows a second preferred embodiment of the device according to the invention.
Figure 3 shows a paving brick layer in zigzag or herringbone pattern.
Figure 4 shows a paving brick layer in stretcher pattern.
The first preferred embodiment shown in figure 1 comprises a gripper 1 for gripping, transporting and laying a paving brick layer. On a first side 2 the gripper 1 comprises a multitude of movable clamping elements 3. On a second side 5 the gripper 1 comprises a fixed clamping element 4. Each movable clamping element 3 is movable between an open position removed from the paving brick layer and a clamping position in which the paving bricks are clamped between the fixed clamping element 4 and the movable clamping element 3. The gripper 1 is provided with means 16 for contacting the upper surface of the paving brick layer. These means 16 are rotatably mounted in the gripper 1 and preferably comprise at least 3 wheels 16 which are rotatable about an axis substantially parallel to the upper surface and about an axis substantially perpendicular to the upper surface of the paving brick layer. In this way, these wheels 16 allow the gripper, while already resting upon the paving brick layer, to be positioned before clamping the paving brick layer.
The three wheels 16 are provided in the gripper at distances from each other such that the gripper 1 is able to rest stably upon the paving brick layer before clamping them. The wheels 16 are preferably adjustable in height direction, such that the thickness of the paving brick layer which is to be laid can be taken into account and it can be ensured that the clamping elements 3 are at a suitable height against the side wall of the paving bricks. The rotatable means 16 for contacting the paving brick layer may however also be constructed in any other way known to the person skilled in the art.
The movable clamping elements 3 on the first side 2 of the gripper 1 are rotatable around a substantially cylindrical axle 6. This cylindrical axle 6 constitutes a common supporting element for the movable clamping elements 3 on the first side 2 of the gripper 1, so that no separate supporting element is needed for each movable clamping element 3 as in the prior art. This has the advantage that the weight of the device according to the invention can be reduced.
For moving the movable clamping elements 3, the gripper 1 preferably comprises hydraulic cylinders 9, one for each movable clamping element 3. These hydraulic cylinders 9 are connected with each other and with a hydraulic coupling 11 by means of hydraulic conduits 10. The hydraulic coupling 11 is provided to couple the hydraulic cylinders 9 on the gripper with a hydraulic drive of a motor vehicle (not shown). For moving the movable clamping elements 3, the gripper may also be provided with pneumatic, mechanic, electric or other drive means known to the person skilled in the art.
Each movable clamping element 3 is preferably at the bottom provided with a foot 7 which is provided to be brought against the side wall of the paving brick layer and which extends over substantially the length of at least two paving bricks. On the second side 5 of the gripper 1, preferably one fixed clamping element 4 is located which extends over substantially the entire length of the second side 5. As the foot 7 extends over substantially the length of at least two paving bricks, at least two rows of paving bricks are clamped between a movable clamping element 3 and the fixed clamping element 4 with the device of figure 1. This could lead to problems, when the paving bricks show irregularities, so that the clamping force on one row is larger than on the adjacent row. This could result in the paving bricks falling out of the layer. In order to prevent this, the fixed clamping element 4 preferably comprises means 8 for overcoming irregularities on a side wall of the paving brick layer contacting the fixed clamping element 4. These means are preferably a multitude of resilient elements, such as for example plates 8, which are mounted next to each other in longitudiunal direction of the fixed clamping element 4. The width of these plates is such that at least one and preferably two or more of these plates 8 come in contact with each row of paving bricks on the second side of the gripper. Due to the resiliency, the plates are able to bend. A plate coming into contact with an irregularity on a paving brick of a paving brick layer to be laid, will bend a little more. This can guarantee that the clamping force on each row of paving bricks is sufficient. The means for overcoming irregularities on the side wall of the paving bricks may however also comprise a rubber strip extending over substantially the entire length of the fixed clamping element 4 and which is located on the side of the fixed clamping element 4 facing the paving bricks, or any other resilient means known to the person skilled in the art. By providing the wide foot 7 and the one oblong fixed clamping element 4, the number of fixed and movable clamping elements can be reduced in comparison with the device known from the prior art. As a result, the weight of the device according to the invention can be reduced.
On a third side 12 substantially perpendicular to the first side 2, the gripper 1 preferably comprises a fixed positioning element 13, which is provided to be brought against a side wall of the paving brick layer. The fixed positioning element 13 extends over substantially the entire length of the third side 12 of the gripper 1. By means of the fixed positioning element 13, the gripper 1 can be positioned with respect to the paving brick layer before it is clamped.
On a fourth side 14 opposite the third side 12, the gripper preferably comprises a movable positioning element 15. This extends over substantially the entire length of the fourth side 14 of the gripper 1 and is movable between an open position removed from the paving brick layer and a contact position in which the paving brick layer is positioned between the fixed positioning element 13 and the movable positioning element 15. The fixed 13 and movable 15 positioning elements are provided to make sure that the gripper 1 is suitably positioned with respect to the paving brick layer before it is clamped. As the fixed 13 and movable 15 positioning elements are brought against opposite side walls of the paving brick layer, they can furthermore prevent that the paving bricks are spread apart upon clamping, i.e. that wide joints are created between the paving bricks.
For moving the movable positioning element 15, the gripper preferably comprises a hydraulic cylinder 17. This hydraulic cylinder 17 is provided to be coupled to a hydraulic drive of a motor vehicle (not shown). In order to bring the movable positioning element 15 against the side wall of the paving bricks, the gripper may however also be provided with pneumatic, mechanic, electric or other drive means known to the person skilled in the art.
The gripper 1 preferably comprises means 21-24 for adjusting the distance between the movable clamping elements 3 in the clamping position and the fixed clamping element 4. The gripper 1 preferably also comprises means 25-28 for adjusting the distance between the fixed positioning element 13 and the movable positioning element 15 in the contact position. By providing these adjusting means, the gripper can be adjusted to grip, transport and lay paving brick layers of different formats.
The substantially cylindrical axle 6, onto which the movable clamping elements 3 are mounted, and the fixed clamping element 4 are preferably fixed to one or more connecting bars 18, 19, 20 which extend in a direction substantially parallel to the third side 12 and the fourth side 14. Preferably the gripper comprises one connecting bar 18 on the third side 12, one connecting bar 20 on the fourth side 14 and a connecting bar 19 substantially in the middle between the third and fourth sides. In this way the connecting bars 18, 19, 20 give sufficient support for the movable clamping elements and the fixed clamping element. The gripper 1 may however also comprise more or less connecting bars.
The cylindrical axle 6 is preferably mounted in drillings 21 in the connecting bars 18, 19, 20 in such a way that it is removable in its longitudinal direction. Thereto, bushes (not shown) are welded in the drillings 21, to which the cylindrical axle 6 is fixed, preferably by means of bolts (not shown). In this way, the axle 6 can be released and can be moved in longitudinal direction when a damaged movable clamping element 3 is to be replaced.
The fixed clamping element 4 is preferably attached to the connecting bars 18, 19, 20 by means of upright plates 22. These plates 22 are preferably each provided with two holes and the connecting bars 18, 19, 20 are each preferably provided with a series of holes 23 each at the same distance from each other for receiving bolts 24 for fixing the fixed clamping element 4 to the connecting bars 18, 19, 20. In this way, the person skilled in the art is able to adjust the distance between the fixed clamping element 4 and the movable clamping elements 3 to the measures of the paving brick layer. The cylindrical axle 6 and the fixed clamping element 4 can however also be fixed to the connecting bars 18, 19, 20 in any other way known to the person skilled in the art.
The fixed positioning element 13 on the third side of the gripper 12 is preferably fixed to one or more, preferably two, further connecting bars 25, 26. These further connecting bars 25, 26 extend in a direction substantially parallel to the first 2 and second side 5 of the gripper 1 and are preferably welded on top of the connecting bars 18, 19, 20. For adjusting the distance between the fixed 13 and the movable positioning element 15 the further connecting bars 25, 26 each preferably comprise two telescopic parts 25', 25" and 26', 26" which can telescope, whereby drillings 27 are provided in both telescopic parts 25', 25", 26', 26" for fixing the telescopic parts to each other by means of bolts 28.
Preferably a grip 29 is situated on the gripper 1, by means of which an assisting skilled person can steer the gripper 1 during the laying of the paving brick layer against already laid paving bricks. In this way it can be prevented that wide joints are created between the already laid paving brick layer and the paving brick layer which is laid against this layer. The grip 29 is preferably a removable U-shaped bar with open ends which is fixed to short lengths of tubing 32. Preferably, two short lengths of tubing are each time provided at the third side 13 and the fourth side 15 of the gripper, such that the grip 29 can be attached to both the third as well as to the fourth side. The short lengths of tubing 32 preferably are directed in such a way that the grip 29 extends at an angle of approximately 45° or more or less with respect to the paving brick layer in the gripper, such that the gripper 29 is sufficiently accessible to the assisting person skilled in the art. The grip 29 can also have any other shape and can be situated at any other position on the gripper 1.
At the top, the gripper 1 is provided with means 30, 31 for attaching the gripper 1 to a holder of a motor vehicle (not shown). These means are preferably constructed in such a way that the gripper 1 is rotatable with respect to the motor vehicle. Thereto, these means preferably comprise two discs 30, 31 which can rotate with respect to each other, whereby a first 30 is fixed with respect to the gripper 1 and a second 31 is rotatable with respect to the first 30. The rotatability of the gripper with respect to the motor vehicle can facilitate the positioning of the gripper above a paving brick layer which is to be laid.
The operation of the device shown in figure 1 is as follows. At first, the movable clamping elements 3 and the movable positioning element 15 are in the open position. The gripper 1, fixed to a holder of a motor vehicle, is let down above a paving brick layer which is to be laid, until the wheels 16 rest upon the paving brick layer. Thereby, it is made sure that the clamping elements 3, 4 and the positioning elements 13, 15 are located along the side walls of the paving brick layer. Preferably, the gripper is also manoeuvred in such a way that the fixed positioning element 13 and the fixed clamping element 4 substantially contact the paving brick layer, so that it can be avoided that the paving bricks are moved when operating the movable positioning element 15 and the movable clamping elements 3. This is advantageous to prevent that the paving bricks of an underlying layer are displaced upon clamping the paving brick layer. Manoeuvring the gripper 1 while the gripper already rests upon the paving bricks is made possible by means of the wheels 16, which by their rotatability can prevent that the paving bricks are pushed apart during the manoeuvring. Subsequently, the hydraulic cylinder 17 is operated such that the movable positioning element 15 is moved from the open position to the contact position. As a result thereof, both positioning elements 3, 4 are contacting the paving bricks. Hereby, the positioning elements do not or only scarcely exercise a clamping force upon the paving brick layer. They are merely provided to facilitate the positioning of the gripper with respect to the paving brick layer and to keep the paving bricks together. Subsequently, the hydraulic cylinders 9 are operated such that the movable clamping elements 3 are moved from the open position to the clamping position. Thereby the paving brick layer is clamped between the movable clamping elements 3 and the fixed clamping element 4. Through the presence of the resilient plates 8 on the fixed clamping element 4 it is achieved that all the paving bricks are clamped with a substantial similar force. Hereafter the gripper 1 is lifted by means of the motor vehicle and moved to the place where the paving brick layer is to be laid down. At this place, the gripper is let down, whereby an assisting skilled person by means of the grip 29 makes sure that the paving brick layer to be laid is brought as close as possible against the already laid paving bricks. Now, subsequently the hydraulic cylinder 17 and the hydraulic cylinders 9 are operated such that subsequently the movable positioning element 15 and the movable clamping elements 3 return to the irrespective open positions. Hereby, the paving brick layer comes loose and falls out of the gripper 1.
The device of figure 1 is adjusted for the gripping, transporting, and laying of paving bricks in herringbone pattern (see figure 3). Thereto, the gripper is provided with means 33 for filling open spaces 59 between paving bricks present in a paving brick layer with a herringbone pattern. These means are preferably wheels 33 which extend in a direction substantially perpendicular to the first side 2 of the gripper and have a diameter substantially equal to the open spaces 59. The wheels 33 are hingedly mounted on the gripper, such that they are movable along their longitudinal direction. Upon clamping a paving brick layer in the herringbone pattern, these wheels 33 fit in the open spaces 59 between the paving brick layer. Because they are rotatable around their wheel axle and because they are movable along their longitudinal direction, they can be easily let down in the open spaces 59 between the paving bricks, since hereby their position can be adjusted with respect to the open spaces 59 in the case it deviates thereof. The wheels 33 will then hinge forward (in the direction of the first side 2) or backward (in the direction of the second side 5). When subsequently the movable clamping elements 3 are put in the clamping position, the paving bricks which are beside the wheels 33 will be pushed against the wheels 33, such that they can not fall out of the paving brick layer upon transport.
When two paving brick layers with the herringbone pattern are laid next to each other with the device of figure 1, one or more open spaces remain, each being able to fit one paving brick. The person skilled in the art can afterwards fill these open spaces by placing a paving brick in them.
When the device of figure 1 is used for laying paving bricks in a rectangular shape, which means in rows and columns, the wheels 33 are taken off from the gripper.
The second preferred embodiment of the device shown in figure 2 comprises a gripper 40 for the gripping, transporting and laying of a paving brick layer. On a first side 41, the gripper 40 comprises first movable clamping elements 45 alternating with first fixed clamping elements 46. On a second side 42 opposite the first side 41, the gripper 40 comprises second movable clamping elements 47 alternating with second fixed clamping elements 48. The clamping elements 45-48 are mounted in such a way that the second fixed clamping elements 48 oppose the first movable clamping elements 45 and the second movable clamping elements 47 oppose the first fixed clamping elements 46. Each movable clamping element 45, 47 is movable between an open position removed from the paving brick layer and a clamping position wherein the paving brick layer is clamped between the movable 45, 47 and the fixed clamping elements 46, 48. Moreover, the fixed 46, 48 and movable clamping elements 45, 47 are positioned with respect to each other in such a way that upon clamping, a first row of paving bricks of the paving brick layer is displaced over a predetermined length, preferably half the length of a paving brick, with respect to a second row of paving bricks adjacent the first row. This means that, viewed in longitudinal direction of the rows of paving bricks, the first movable clamping elements 45 in the clamping position are located at a predetermined distance, preferably equal to half the length of a paving brick, from the first fixed clamping elements 46. Correspondingly, viewed in longitudinal direction of the rows of paving bricks, the second movable clamping elements 47 in the clamping position are located at a predetermined distance, preferably equal to half the length of a paving brick, from the second fixed clamping elements 48. The device of figure 2 is suitable for laying paving bricks in the "stretcher" pattern, which is known to the person skilled in the art (see figure 4).
As in the device of figure 1, the gripper shown in figure 2 comprises wheels 55 which are provided to allow the gripper 1 to rest upon the paving bricks in such a way that the gripper can be positioned even more accurately before clamping, substantially without that the paving bricks are thereby spread apart. In the device of figure 2, these wheels 55 have an additional function: they allow the paving bricks to be displaced with respect to each other to the stretcher pattern, substantially without that the contact with the gripper impedes herewith. Consequently, the wheels 55 aid in preventing that the paving bricks spread apart during the relative displacement .
The device shown in figure 2 comprises two first movable clamping elements 45, with one first fixed clamping element 46 in between, and two second fixed clamping elements 48, with one second movable clamping element 47 in between. The device shown in figure 2 is thus suitable for picking up a paving brick layer with three rows. However, the second embodiment of the device can also have more or less fixed and movable clamping elements, such that the device is suitable for picking up a paving brick layer with two, four, or more rows.
The first movable clamping elements 45 on the first side 41 of the gripper 40 are rotatably mounted around a substantially cylindrical axle 6. The second movable clamping elements 47 on the second side 42 of the gripper 40 are rotatably mounted around a second substantially cylindrical axle 50. The cylindrical axles 49 and 50 constitute each time a common supporting element for the movable clamping elements 45, 47 on the respective side 41, 42 of the gripper 40. This has the advantage that the weight of the device according to the invention can be reduced.
For moving the movable clamping elements 45, 47, the gripper 40 preferably comprises hydraulic cylinders 51, one for each movable clamping element 45, 47. These hydraulic cylinders 51 are connected with each other and with a hydraulic coupling 52 by means of hydraulic conduits 53. The hydraulic coupling 52 is provided to couple the hydraulic cylinders 51 on the gripper to a hydraulic drive of a motor vehicle (not shown). To bring the movable clamping elements 45, 47 against the side wall of the paving brick layer, the gripper may also be provided with pneumatic, mechanic, electric or other drive means known to the person skilled in the art.
On a third side 43 substantially perpendicular to the first side 41, the gripper 40 preferably comprises a fixed positioning element 54, which is provided to be brought against a side wall of the paving brick layer. The fixed positioning element 54 extends over substantially the entire length of the third side 43 of the gripper 40.
On a fourth side 44 opposite the third side 43, the gripper 40 preferably comprises a movable positioning element (not shown). This extends over substantially the entire length of the fourth side 44 of the gripper 40 and is movable between an open position removed from the paving brick layer and a contact position in which the paving brick layer is positioned between the fixed positioning element 54 and the movable positioning element. The fixed 54 and movable positioning elements are provided to make sure that the gripper 40 is suitably positioned above the paving brick layer before clamping them. Furthermore, the fixed and the movable positioning element can prevent that the paving bricks are spread apart upon clamping, i.e. that wide joints are created between the paving bricks.
For moving the movable positioning element, the gripper preferably comprises a hydraulic cylinder (not shown). This hydraulic cylinder is provided to be coupled to a hydraulic drive of a motor vehicle (not shown). In order to move the movable positioning element, the gripper may however also be provided with pneumatic, mechanic, electric or other drive means known to the person skilled in the art.
The gripper 40 preferably comprises means (not shown) for adjusting the distance between the movable clamping elements 45, 47 in the clamping position and the fixed clamping elements 46, 48. The gripper 40 preferably also comprises means (not shown) for adjusting the distance between the fixed positioning element 54 and the movable positioning element (not shown) in the clamping position. In this way, the gripper 40 can be adjusted to grip, transport and lay paving brick layers of different formats in the stretcher pattern.
As in the device shown in figure 1, the gripper 40 of the device shown in figure 2 preferably comprises a grip 56 and means (preferably discs) 57, 58 for attaching the gripper 40 to a holder of a motor vehicle. These parts substantially correspond in the embodiments shown in figure 1 and 2 and are not described in detail.
The operation of the device shown in figure 2 is as follows. At first, the movable clamping elements 45, 47 and -if present on the gripper- the movable positioning element (not shown) are in the open position. The gripper 40, attached to the holder of a motor vehicle, is let down above a paving brick layer which is to be laid until the wheels 55 rest upon the paving brick layer. The paving brick layer comprises alternating first and second rows, whereby in the beginning the joints between the paving bricks are in line, which means that the paving brick layer has a rectangular shape. Thereby it is made sure that the clamping elements 45-48 are located along the side walls of the paving brick layer. The gripper 40 is manoeuvred in such a way that the fixed positioning element 54 contacts the paving brick layer. When the movable positioning element is present, it is subsequently brought into the contact position. When it is not present, the gripper is manoeuvred such that the fixed positioning element 54 pushes together the paving bricks, meaning that wide joints between the paving bricks are pushed together as much as possible. Subsequently, the hydraulic cylinders 51 are operated such that the movable positioning elements 45, 47 are moved from the open position to the contact position. Thereby, the movable clamping elements 45 push the first rows of paving bricks against the second fixed clamping elements 48. Correspondingly, the second movable clamping elements 47 push the second rows of paving bricks against the second fixed clamping elements 48. As a result, with the movable clamping elements 45, 47 in the clamping position, the first rows of paving bricks are displaced over half the length of a paving brick with respect to the second rows of paving bricks. Hereafter, the gripper 40 is lifted by means of a motor vehicle and is transported to the place where the paving brick layer is to be laid down. The gripper is let down at this place, whereby an assisting person skilled in the art by means of the grip 56 makes sure that the paving bricks in the gripper 40 that are to be laid are brought as close as possible against the already laid paving bricks. If the gripper 40 comprises the movable positioning element (not shown), this is now first brought in the open position. Subsequently the hydraulic cylinders 51 are operated such that subsequently the movable clamping elements 45, 47 return to the respective open position. Hereby, the paving brick layer comes loose and falls out of the gripper 1.
As in both described embodiments the gripper 1, 40 has a smaller weight than in the device known from the prior art, the motor vehicle for operating the gripper 1, 40 can also have a smaller weight than in the device known from the prior art. In the device according to the invention, the motor vehicle can have a lower weight, as the weight of the motor vehicle has to form a small counterweight for the weight of the gripper. The gripper of the device according to the invention can be operated by means of a so called 'rollmop', whereas in the device known from the prior art a so called 'bobcat' needs to be used for operating the gripper. Both motor vehicles are known to the person skilled in the art. It is also known to the person skilled in the art that a rollmop in general has a lower weight than a bobcat. The gripper 1, 40 of the device according to the invention can however also be operated by means of any other motor vehicle than a rollmop which is considered suitable to the person skilled in the art.

Claims

A device for laying paving bricks, comprising a gripper for gripping, transporting and laying a paving brick layer, the gripper on at least a first side (2; 41) comprising at least one movable clamping element (3; 45; 47), each movable clamping element (3; 45; 47) being movable between an open position removed from the paving brick layer and a clamping position for clamping the paving brick layer against a fixed clamping element (4; 46; 48) at a second, opposite side (5 ; 42) of the gripper (1; 40), the gripper (1; 40) being provided with means (16; 55) for contacting an upper surface of the paving brick layer, characterized in that these means (16; 55) are rotatably positioned in the gripper (1; 40) to allow a positioning of the gripper before clamping the paving brick layer and while these means (16; 55) are contacting the upper surface of the paving brick layer.
A device according to claim 1, characterized in that the means (16; 55) comprise at least three wheels (16; 55), which on the one hand are rotatable about an axis substantially parallel to the upper surface of the paving brick layer and on the other hand are rotatable about an axis substantially perpendicular to the upper surface of a paving brick layer.
A device according to claim 2, characterized in that the gripper (1; 40) at a third side (12; 43) substantially perpendicular to the first side (2; 41) is provided with a fixed positioning element which extends over substantially the entire length of the third side and is provided to be positioned against a side wall of the paving brick layer.
A device according to claim 3, characterized in that the gripper (1; 40) at a fourth side (14; 44) opposite the third side (12; 43) is provided with a movable positiong element (15) which extends over substantially the entire length of the fourth side and which is movable between an open position removed from the paving brick layer and a clamping position in which the paving brick layer is positioned between the fixed (13; 54) and the movable positiong element (15).
A device according to any one of claims 1-4, characterized in that the at least one movable clamping element (3; 45; 47) is rotatably mounted around a substantial cylindrical axle (6; 49; 50) extending in the direction of the first side (2; 41).
A device according to any one of claims 1-5, characterized in that each movable clamping element (3) on the first side (2) of the gripper (1) comprises at its bottom a foot (7) which is provided to be brought against a side wall of the paving brick layer and which extends over substantially the length of at least two paving bricks.
A device according to any one of claims 1-5, characterized in that the gripper (1) comprises one fixed clamping element (4) on the second side (5), which extends over substantially the entire length of the second side (5) and which is provided with means for overcoming irregularities on the side wall of the paving brick layer with which the fixed clamping element comes into contact.
A device according to claim 7, characterized in that the means for overcoming irregularities comprise a multitude of resilient plates (8) which are mounted next to each other in longitudinal direction of the fixed clamping element (4) on the second side (5) of the gripper (1).
A device according to any one of claims 1-8, characterized in that the gripper (1) is provided with means (33) for filling open spaces between paving bricks of a paving brick layer in the herringbone pattern.
A device according to claims 9, characterized in that the means for filling open spaces are wheels (33) which extend in a direction substantially perpendicular to the first side (2) of the gripper (1) and have a diameter substantially equal to the width of the open spaces between the paving bricks.
A device according to any one of claims 1-5, characterized in that the gripper (40) on the first side (41) comprises first movable clamping elements (45) alternating with first fixed clamping elements (46) and on the second side (42) comprises second movable clamping elements (47) alternating with second fixed clamping elements (48), mounted in such a way that the second fixed clamping elements (48) oppose the first movable clamping elements (45) and that the second movable clamping elements (46) oppose the first fixed clamping elements (47), whereby the fixed and movable clamping elements (45-48) oppose each other in such a way, that upon clamping a first row of paving bricks of the paving brick layer is displaced over a predetermined length with respect to a second row of paving bricks adjacent the first row.
A device according to any one of the preceding claims, characterized in that the gripper (1; 40) is provided with means (25-28) for adjusting the distance between each movable clamping element (3; 45; 47) in the clamping position and the opposite fixed clamping element (4; 46; 48).
A device according to any one of claims 3-12, characterized in that the gripper (1; 40) is provided with means (21-24) for adjusting the distance between the fixed (13; 54) and the movable positioning element (15) in the contact position.
A device according to any one of the preceding claims, characterized in that the means (16; 55) for contacting the upper surface of the paving brick layer are adjustable in height direction.