EP3124407A1 - Conveyor device for a paver or feeder - Google Patents

Abstract

Described is a conveyor device (14) for a paver or a feeder, comprising a revolving flexible conveyor (114, 214) and a tensioning device (40) for tensioning the conveyor, wherein the conveying means is guided over at least two rollers, wherein at least one of the rollers (142) is fixedly mounted to a frame (25), and one of the rollers is a tension roller (143) which is slidable relative to the frame, the tension device being connected to the frame at a first end and at a second end the tensioning roller acts, wherein the tensioning device comprises at least one hydraulically loadable tensioning means (41).

Description

TECHNICAL AREA

The present description relates to a conveyor device for a paver or feeder as described in claim 1. It further relates to a paver and a feeder, and a hydraulic control device according to the further independent claims, as well as a method for operating the conveyor.

TECHNOLOGICAL BACKGROUND

Road pavers include a tractor and towed vehicles. During the installation process, a paving material, for example a bituminous mass, is conveyed from a bunker lying in front in the direction of travel of the tractor to a dumping position lying behind the chassis of the tractor in the direction of travel, where it is deposited on the surface. The Tractor tows the mounting means, which include, for example, a screed, on the built-in, wherein the stored in front of the installation means built-in compacted by the mounting means and optionally contoured. The mounting means may comprise a rammer, details of the mounting means being of no concern to the further embodiments of the present description. Furthermore, a transverse distributor can be arranged. The tractor comprises conveying means with which the built-in material is conveyed from the material bunker lying in the direction of installation to a discharge position and thus to the installation means. These are usually spread as rotating funding. Known are so-called scraper belts, in which two laterally running chains in the conveying direction are arranged with webs extending transversely between the chains. With a circulation of the chains, the webs pull the built-in with him and promote it from the bunker to the dumping and thus to the installation means.

Furthermore, so-called feeders are known, which serve to promote material by means of a conveyor, for example, between a truck and a paver.

It is known to provide at least one clamping device, which ensures that the rotating conveyor are always under tension and to prevent vibrations of the conveyor and / or a jumping off of the conveyor of the drive and / or guide rollers of the conveyor. The tension of the conveying means can be adjusted, for example, by setting the distance of at least one frame-fixed roller and at least one tensioning roller, via which the conveying means are guided, in such a way that a certain tension of the conveying means results.

If, for example, individual chain links run over a deflection or if foreign bodies are drawn in between the circulating conveying means and a roller, the available free path length of the conveying means changes between the rollers arranged in the direction of rotation of the conveying means, which results in a change in the tension of the conveying means results, provided not an axial distance is adjusted within the conveyor. On the other hand results over the service life of the conveyor an elongation of the conveyor and thus a loss of voltage, unless also an axial distance is increased accordingly. Thermal differential strains can also lead to a change in the existing conditions.

PRESENTATION OF THE SUBJECT OF THE PRESENT DESCRIPTION

It is an improved conveyor for a paver or a feeder to be specified. According to one aspect of the present description, a conveying device for a paver or a feeder is to be specified, with which a constant tension of the conveying means can be ensured in the long-term operation. According to a further aspect, the conveying device should require a low maintenance requirement. In a further aspect, the conveying device should be specified in such a way that a correct tensioning of the conveying means is guaranteed, which does not depend on manual adjusting operations.

Other effects and advantages of the objects described herein, whether explicitly stated or not, will become apparent in light of the present description.

This is achieved by means of the subject matter described in claim 1. This is further achieved by means of the objects described in the further independent claims.

Described is therefore a conveyor device for a paver or a feeder, which comprises a rotating bendable conveyor and at least one clamping device for clamping the conveyor, wherein the conveyor is guided over at least two rollers, wherein at least one of the rollers is fixedly mounted to a frame and at least one of the roles one Tensioner pulley, which, or the axis thereof, is displaceable relative to the frame, wherein the tensioning device is connected at a first end to the frame and acts on the tensioning roller at a second end, and wherein the tensioning device comprises at least one hydraulically loadable tensioning means. Subsequently, the first end of the clamping device is also referred to as a fixed end and the second end as a loose end of the clamping device.

In contrast to an elastic clamping means, such as a spring, a hydraulically loadable clamping means, when it is subjected to a constant hydraulic pressure, regardless of its deflection always a constant clamping force. For example, while in a coil spring, the applied force acting in the longitudinal direction decreases with the length of the spring remains in a hydraulic cylinder, the longitudinal force regardless of the position of the piston in the cylinder, ie regardless of the deflection of the clamping device, always the same, provided that hydraulic working pressure of the clamping device is kept constant. In other words, the force applied by a hydraulically loadable clamping means is dependent on the hydraulic working pressure, but independent of the deflection of the clamping means. That is, in a wear-induced elongation of the conveyor, the applied clamping force over the service life of the conveyor can be kept constant. Likewise, a replacement of the conveyor automatically results in a correct clamping force. Operational safety is significantly increased, and the maintenance required to ensure proper tensioning of the conveyor is eliminated. The bendable conveying means is for example a conveyor belt or a scraper belt, as described above. In particular, the clamping device acts on a tensioning roller over which the conveying means is guided. In a conventional manner, the distance between the deflection and / or tensioning roller is made variable from the axes of further drive and / or deflection and / or tensioning rollers. It is readily apparent to one skilled in the art that the idler and / or idler is particularly unpowered, but need not be. The deflection and / or tensioning roller is also referred to as a tensioning roller in the following. It is further understood that the term "role" within the meaning of the present disclosure broadly understand, as an element over which the conveyor unrolls. A role may be contoured in this sense on its outer circumference, for example as a gear. This is readily apparent to those skilled in the art. The tensioning device exerts a force on the tensioning roller, and shifts the tensioning roller relative to other, frame-fixed rollers until the desired clamping force of the conveyor is set. The tensioning device thus displaces the tensioning roller until an equilibrium of forces is set between the forces applied by the tensioning force of the conveying means and the tensioning device to the tensioning roller. In particular, an axis of a tension roller is held on the second, loose end of the tensioning device. The axle may be guided at the loose end of the tensioner in a bearing that allows rotation of the axle. Likewise, the axis may be held firmly about its axis of rotation at the loose end of the tensioning device, wherein at least one tensioning roller is mounted rotatably about the axis on this. Furthermore, the axis may be pivotally and pivotally connected to the tensioning device, such that no moments are introduced into the tensioning device.

A change in the deflection of the hydraulically actuable clamping means is effected by hydraulic fluid is supplied to the clamping means or derived from the clamping means. The force applied by the hydraulically loadable clamping means is adjustable via a hydraulic working pressure. It may be provided that means are provided in flow paths through which hydraulic fluid can be supplied to the hydraulically loadable tensioning means or via which hydraulic fluid can be discharged from the hydraulically loadable tensioning means, means are provided which generate a flow resistance. These means act as delay elements for a deflection change of the hydraulically loadable clamping means. This is because, due to the flow resistance generated, hydraulic fluid can not flow rapidly to or flow away from the hydraulically loadable clamping device. This will be explained in more detail below. In this case, a delay is not to be understood as meaning that the change in the deflection of the hydraulically actuated clamping means does not take place until after a certain time, but that this is slowed down, in the regulatory sense of a delay element.

In particular, the tensioning device has a longitudinal extent between its first, fixed end and the second, loose end, and is designed so that it can apply a force acting along the longitudinal extension force which is further directed in particular from the fixed end to the loose end.

The hydraulically loadable clamping means is, for example, a hydraulic cylinder, and may furthermore, in particular, be a single-acting hydraulic cylinder. In one embodiment, the piston side of the hydraulic cylinder can be acted upon by a hydraulic pressure. This can be applied with the same hydraulic pressure, a greater force than when an impact of the piston rod side. Furthermore, it can be provided that the hydraulic cylinder is arranged with its cylinder towards the frame or that the cylinder is connected to the frame. The cylinder may in particular be attached to the frame. The hydraulic cylinder acts in this case with the piston rod indirectly or directly on the tension roller of the conveyor, or on an axis of the tension roller.

By means of the hydraulically loadable clamping means, it is possible that the force acting on the conveyor clamping force can be kept constant regardless of the deflection of the clamping device. In another aspect, the hydraulic tensioner may be configured to maintain the tensioning force on the conveyor within certain limits.

In certain embodiments of the subject matter described herein, one or more hydraulically actuable tensioning means is or are provided as the tensioning means of the tensioning device.

Using a hydraulically loadable clamping means can be adjusted in a simple manner via a control and / or regulation of the pressure, the voltage of the conveyor and this by changing the Deflection of the clamping device or the hydraulically acting clamping means are regulated or adjusted. On the one hand, it can be ensured that the tension of the conveying means is kept constant over the long term, that is to say in the case of use-related elongation of the conveying means. There is no maintenance required. On the other hand, it can be provided that the tensioning device reacts to short-term and, in particular, periodically occurring changes in the clamping force slowed down by a change in its deflection. Thus, for example, a swinging up of the entire conveyor is avoided. Means may also be provided for limiting the force applied by the tensioning device. Overall, the useful life of the conveyor is significantly increased, improves the reliability and reduced maintenance.

In further embodiments of the conveying device, the tensioning device comprises at least one elastic tensioning means, wherein the hydraulically loadable tensioning means and the elastic tensioning means are arranged in a series connection. Thus, for example, at least one hydraulically loadable clamping means may be connected in a longitudinal direction of the clamping device with at least one elastic clamping means. The elastic tensioning means is for example a spring, for example a helical spring and / or a plate spring.

The tensioner includes, in certain embodiments, a pressure accumulator.

There continue to be short-term and possibly cyclic effects which influence the tension of the conveyor and / or the necessary for a constant tension center distance between the frame-fixed rollers and the idlers. Thus, when unrolling a chain, which is part of the conveyor in certain embodiments of the conveyor, the free length of the conveyor between two axes of the conveyor changes continuously and cyclically by a small amount. This results in changes in the force acting on the jig, whereupon the Clamping device reacts by a change in length. Likewise, especially in the case of a conveying device for a road paver or a feeder, it must be expected that foreign objects, such as stones, will be trapped between a roller and the conveyor. Upon the occurrence of said short-acting effects hydraulic fluid from the hydraulically loadable clamping means can flow into the pressure accumulator and flow out again, so as to allow a change in length between the frame-fixed and the free end of the clamping device. It is thus possible that the hydraulically actuated clamping means can work without each due to such short-term changes in the force acting on the hydraulically acting clamping force continuously hydraulic fluid from a hydraulic supply system to be removed from the hydraulically actuated clamping means and fed back to the hydraulically actuated clamping means. This ensures a low-loss and economical operation of the hydraulically loadable clamping device. As a pressure accumulator, for example, a hydropneumatic pressure accumulator application in which a compressible gas cushion allows the inflow and outflow of hydraulic fluid.

Alternatively or in addition to the pressure accumulator may be arranged said elastic clamping means, which is connected in series with the hydraulically loadable clamping means. As a result, the hydraulically loadable clamping means and the elastic clamping means are loaded with the same force. The elastic clamping means compensates small and short-acting length changes, which of course changes the acting clamping force with the change in length of the elastic clamping means. The hydraulically actuated clamping means reacts, for example, in the manner described above with a time delay to the change in the hydraulic pressure caused thereby and / or acts as a clamping force limiter.

The desired value of the clamping force as well as the dynamic behavior of the clamping device can be adjusted via a suitable running control device for supplying the hydraulically actuated clamping means.

In further embodiments of the conveying device, the hydraulically loadable clamping means is connected to a hydraulic control device. In a hydraulic flow path between a hydraulic pressure port and the clamping means, a pressure control member is arranged, which is provided and arranged to adjust the hydraulic pressure in a working space of the hydraulically loadable clamping means to a desired value.

In a further development of the preceding embodiment, the hydraulic control device comprises a means for increasing the flow resistance of the hydraulic fluid flowing back from the hydraulically loadable clamping means to the pressure control member, which is arranged in a hydraulic flow path between the pressure control member and the hydraulically actuated clamping means. This agent is referred to below as Rückflussbegrenzer. By means of the reflux restrictor, the volumetric flow of the hydraulic fluid flowing back from the hydraulically loadable clamping device to the pressure control member can be reduced. This ensures that with an increase in pressure in the hydraulically loadable clamping means due to a force acting on the hydraulically actuated clamping means force delay time or with a time constant hydraulic fluid can flow through the pressure control element. The pressure control element, a pressure control loop, as well as the conveyor are thus secured against swinging. Since the volumetric flow of the hydraulic fluid flowing back from the hydraulically loadable tensioning means is reduced, reliable and economical operation of the tensioning device is furthermore ensured. The Rückflussbegrenzer can be realized by a check member and a throttle body between the pressure control member and the hydraulically acting clamping means are arranged in parallel, wherein the non-return member is arranged with its flow direction from the pressure control member to hydraulically acted clamping means. In particular, a pressure accumulator of the type described above may be connected to a hydraulic flow path which is between the hydraulically loadable clamping means and the reflux limiter is arranged. In this accumulator hydraulic fluid can be temporarily stored, which flows out of the hydraulically acted clamping means and the return flow is hindered to the pressure control member due to the Rückflussbegrenzers.

Furthermore, a pressure limiting member may be provided, which is arranged in a return flow path, which leads from the hydraulically loadable clamping means to a tank connection, and whose pressure limit is greater than the desired value of the inlet pressure. This ensures that, in the event of a sharply increasing clamping force above a permissible limit value, hydraulic fluid can quickly and reliably flow out of the hydraulically loadable clamping device without the entire outflowing volume flow having to flow via the pressure control element. The hydraulic control device can quickly respond to excessively high tension forces that would be likely to damage or otherwise mechanically overload the conveyor or other components of the conveyor. Below a maximum allowable clamping force, which is set by the pressure limit of the pressure limiting member, the clamping force can be controlled with a time delay as described above.

It may further be provided that a further return line is provided between the hydraulically loadable clamping means and a tank or a tank connection, which is provided with a manually operable shut-off member. This makes it possible to relieve the hydraulically loadable clamping means during maintenance of the conveyor device, for example in a necessary replacement of the conveyor.

In particular, the tensioning device comprises hydraulic connections, which are provided to be connected to a hydraulic supply system. In this respect, a conveying device of the type described above is also described, which is connected to the hydraulic supply system of a paver or a feeder.

The conveying means of the conveying device comprises, for example, a link chain. The conveyor is, for example, a scraper belt.

According to another aspect of the present invention, the conveyor is a conveyor for a paver, the paver comprising mounting means, and wherein the conveyor is adapted and provided to convey dug from a paver bunker of the paver to the installation means.

Further described are a paver and a feeder comprising a conveyor of the type described above, and wherein the frame of the conveyor is a chassis of the paver or the feeder.

There is further described a paver and a feeder comprising a bunker for paving, and further comprising a conveying device of the type described above which is adapted, provided and arranged for paving material from the bunker to, for example, before a paver's installation means arranged, discharge position of the paver or the feeder to promote.

Furthermore, a hydraulic control device for a conveying device of the aforementioned type is described, wherein the control device is designed according to the above-mentioned embodiments relating to a hydraulic control device.

The hydraulic control device accordingly comprises a pressure control member, which on the one hand comprises a pressure connection for hydraulic fluid and a return connection, and on the other hand comprises an output connection, which is provided to be connected to the hydraulically loadable clamping means. The pressure control member is in a known per se, a hydraulic control member, which is executed and provided, in dependence on the pressure present at the output port, the output terminal bring the pressure port and / or the return port in fluid communication.

In one embodiment of the hydraulic control device, this includes a hydraulic flow path from the output port of the pressure control member to a port for a hydraulically actuated clamping means. In this hydraulic flow path, a reflux restrictor is arranged as described above. Furthermore, a pressure accumulator may be provided and connected in such a way that it is in fluid communication with the hydraulic flow path between the reflux limiter and the hydraulically loadable tensioning means. It may further be provided that a hydraulic return flow path is arranged from the hydraulically actuable clamping means to a return port. In said hydraulic flow path, a pressure limiting member is arranged. In particular, a pressure limit of the pressure limiting member is greater than the control pressure of the pressure control member. Furthermore, a return line can be provided by the hydraulically acted clamping means, in which a manually operable shut-off device is arranged.

Furthermore, a method for operating a conveying device, in particular in a paver or a feeder, is specified. The conveying device is, for example, a scraper belt conveyor, which is intended to convey material from a built-in bunker of a road paver to the installation means of the paver. The method comprises providing a revolving flexible conveyor and applying a tensile force to the conveyor to place the conveyor under tension. The force is applied by at least one hydraulically loadable clamping means. The method may further comprise applying a controlled hydraulic pressure to the hydraulically actuable clamping device. The method may also include limiting the return flow of hydraulic fluid from the hydraulically actuable clamping means to a pressure control member. Furthermore, it can be provided from the at least partially introduce hydraulic fluid flowing out hydraulically actable clamping means in a pressure accumulator.

The above-described embodiments of the described objects can of course be combined with each other. Further, non-specifically disclosed embodiments of the teaching of this document are readily apparent to those skilled in the art.

BRIEF DESCRIPTION OF THE FIGURES

Fig. 1

einen Strassenfertiger, welcher eine Fördervorrichtung zur Förderung von Einbaugut aus einem Einbaugutbunker zu einer Bohle umfasst;

Fig. 2

eine Seitenansicht eines Kratzerbandförderers als Beispiel für eine Fördervorrichtung der vorliegend beschriebenen Art;

Fig. 3

eine Draufsicht auf eine erste beispielhafte Ausführungsform eines Kratzerbandförderers für einen Strassenfertiger, welcher gemäss der vorliegend beschriebenen Lehre ausgeführt ist;

Fig. 4

eine beispielhafte Ausführungsform einer Drucksteuervorrichtung, welche zur Steuerung des Arbeitsdrucks von hydraulisch beaufschlagbaren Spannmitteln in einer Fördervorrichtung der vorliegend beschriebenen Art geeignet ist;

Fig. 5

eine Draufsicht auf eine zweite beispielhafte Ausführungsform eines Kratzerbandförderers für einen Strassenfertiger, welcher gemäss der vorliegend beschriebenen Lehre ausgeführt ist.

The facts presented here are explained in more detail below with reference to selected embodiments shown in the drawing. Show in detail

Fig. 1

a paver comprising a conveyor for conveying slug from a slaughter bin to a screed;

Fig. 2

a side view of a scraper belt conveyor as an example of a conveying device of the type described herein;

Fig. 3

a plan view of a first exemplary embodiment of a scraper belt conveyor for a paver, which is carried out according to the teachings described herein;

Fig. 4

an exemplary embodiment of a pressure control device which is suitable for controlling the working pressure of hydraulically loadable clamping means in a conveying device of the type described herein;

Fig. 5

a plan view of a second exemplary embodiment of a scraper belt conveyor for a paver, which is designed according to the teaching described herein.

The drawings are very schematic. Details not necessary for understanding the described objects have been omitted. Furthermore, the drawings show only selected embodiments and should not be used to limit the objects described in the claims. Not shown embodiments may well be covered by the claims.

EMBODIMENTS

The FIG. 1 shows a paver 1, comprising a tractor 10 and a plank 20. In the present case, a tracked paver is shown. It is understood that the following explanations also apply to a wheeled paver. The tractor 10 includes a drive 11, a chassis 12, and a built-in bunker 13. The screed 20 is coupled by means of support arms 17 to the tractor. By means of hydraulic cylinders 15 and 16, the screed 20 can be raised and lowered. When finishing a road surface, the paver moves in the direction shown by the arrow 2. Built-in material is conveyed by means of scraper belt conveyors 14, which are only partially visible in this illustration, out of the built-in bunker 13 onto the flat 31 in the direction of travel behind the tractor and in front of the screed. Deposit material 32 deposited there is distributed by means of a worm 22 in the width of the screed, pressed down by a rammer 23, which moves alternately upwards and downwards, and finally compacted by a sliding plate 24 of the screed by the weight of the screed resting thereon and smoothed. In this way, behind the road paver, a smoothed and optionally contoured roadway surface 33 is created.

In FIG. 2 schematically a side view of a scraper belt conveyor 14 is shown as an example of a conveying device of the type described. The scraper belt conveyor comprises a chain 141, which is guided over a drive roller 142 and a tensioning roller 143. The drive roller and the tension roller are each designed as sprockets, on the teeth of the chain 141 unrolls. Two of the chains mentioned are arranged parallel to one another in the axial direction of the rollers 142 and 143. In the present illustration, only one of these chains is visible. Another, not visible in the present illustration, chain is guided in an identical manner via a drive roller and a tensioning roller. Between the two chains are arranged in a likewise not shown, but well-known way, transverse webs. The chains form together with the transverse webs a circumferential bendable conveying means which is driven by the drive rollers 142 in the conveying direction indicated by F. During operation of the conveyor, the transverse webs run in the Zugtrum overhead in the present presentation on a plate 144. The transverse webs promote material lying on the plate 144 in the conveyor on the plate. In this way, as related to FIG. 1 can be seen, built-in property of a built-in bunker a paver to be conveyed to a lying in front of the Bohle discharge position. The drive roller 142 is mounted stationary to a frame 25. This frame may be, for example, the chassis of a paver. A tensioning device 40 is attached at a first end to the frame 25 and acts at its second end on the tension roller 143. The second end of the tensioning device 40 and the tensioning roller 143 are slidably disposed relative to the frame 25. That is, the tensioning device is designed such that the first end of the tensioning device and the second end of the tensioning device are displaceable relative to one another in a longitudinal direction of the tensioning device. The tensioning device is further configured such that a force directed in the longitudinal direction of the tensioning device from the first end to the second end is applied, which endeavors to remove the first and the second end of the tensioning device from one another. In this way, a tension of the rotating bendable conveying means can be ensured by the tension of the chain 141.

FIG. 3 shows a schematic plan view of a parallel arrangement of two scraper belts 114 and 214, as found, for example, in a paver for conveying the material to be installed by the bin bin to the installation means, for example, the screed application. A first pair of chains 1411 and A second pair of chains 1413 and 1414 forms a second scraper belt 214 with interposed, not shown, transverse webs arranged between them. The arrangement of the transverse webs between each two chains in a scraper belt is familiar to the expert, which is why the transverse webs are not shown in the sense of clarity. Likewise, the plates 144 from the FIG. 2 not shown in the sense of a better clarity and representability of the essential elements. The chains run on the one hand via drive rollers 142, which are arranged on a common drive shaft 148. The drive shaft 148 is fixedly mounted to the frame 25. At both ends of the drive shaft 148 drive pinion 149 are arranged. About this, the drive shaft and thus the drive rollers can be driven. The chains are still guided over idlers 143. The tension rollers of each scraper belt 114 and 214 are rotatably mounted on a respective common axis 146 by means of bearings 145. For the tension rollers of each scraper belt 114 and 214, a separate axle 146 is provided, on which the tension rollers assigned to the respective scraper belt are mounted. The axes are provided at their ends with guide pieces 147. The guide pieces are guided in longitudinal grooves of linear guide elements 26, such that they are displaceable in the linear guide elements along the longitudinal extension of the tensioning devices or in the illustrated embodiment of the tensioning strand of the chains, as well as perpendicular to the axial direction of the respective axis 146. In a direction perpendicular thereto, which is also perpendicular to the axial direction of the axis 146, the guide pieces, however, are fixed, apart from a possible game. Furthermore, each axis 146 is held axially fixed along its axial direction between two linear guide elements, with a play of up to a few millimeters is possible in the axial direction. The guide pieces 147 further have rounded outer surfaces, such that the axis 146 can tilt by both ends of an axis 146 are moved differently far in the linear guide. The effect achieved by this is described in more detail below. The axle 146 is connected to a tensioning device 40. The clamping device 40 is in the present embodiment, a single-acting hydraulic cylinder 41, which at a End is firmly connected to the frame 25. At a second, formed by a piston rod 42 of the hydraulic cylinder, the end of the tensioning device is pivotally connected to the axis 146. Now, if the hydraulic cylinder 41 is acted upon by the piston side with a pressurized hydraulic fluid, acting on the piston rod and thus to the second end of the tensioning device towards the force acting on the piston of the hydraulic cylinder. This force acts via the piston rod 42 on the axis 146 and thus on the tension rollers mounted thereon, and thus causes a voltage of the guided over the tension rollers chains. Due to the use of a hydraulically loadable clamping means, such as the hydraulic cylinder 41, the applied force is independent of the deflection of the clamping means. That is, regardless of the length of the chains and the associated deflection of the clamping means, the applied clamping force can be kept constant. Characterized in that the axis 146 is pivotally connected to the piston rod 42, acting on the piston rod bending moments are avoided. The piston rod is articulated in particular centrally between the tension rollers on the axle. This results in a moment equilibrium around said pivot point when both the tension rollers of an axis guided chains, for example, 1411 and 1412 or 1413 and 1414, acted upon by the same clamping force. With an unequal length of the two chains of a scraper belt, the axle 146 tilts about the pivot point between the axle and the piston rod. This is made possible in particular by the rounded outer surfaces of the guide pieces 147. In any case, both chains remain tensioned with the same force. The same applies if a foreign body between one of the chains and the associated tension pulley or drive roller works. In this case, on the side on which a foreign body is located between a roller and the chain, the tension roller is pulled toward the drive roller. The tension roller of the other chain remains in its original position. The clamping device, and in the example shown, the hydraulic cylinder 41, thereby executes a stroke corresponding to half the movement of the moving tension roller. The clamping force, which acts on the axis 146 via the piston rod 42, is dependent solely on the pressure of the hydraulic fluid in the hydraulic cylinder and can be kept constant. As will be shown below, it can the time behavior of the force via a control of the cylinder flowing or flowing out of the cylinder hydraulic fluid flow rates can be influenced. In any case, the tension of both chains of a scraper belt remains constant, as must continue to adjust a torque balance around the pivot point between the axis and the piston rod.

In the FIG. 4 an exemplary hydraulic control device is shown, which can be used in conjunction with the proposed conveyor to control or regulate the working pressure of the hydraulically loadable clamping means and the hydraulically loadable clamping means flowing and flowing from this hydraulic fluid volume flows. A pump 51 delivers hydraulic fluid from a tank 52 to the control device 50. The hydraulic fluid delivered by the pump flows to a pressure control member or pressure regulating member 53. This regulates the pressure at its outlet or in a hydraulic fluid flow path 61 which is between a hydraulic fluid flow. Pressure connection 65 and the hydraulically actuated clamping means is arranged, to a set value of, for example, 120 bar. When the pressure at the output side of the pressure regulating member is below the target value, the pressure regulating member 53 opens a flow path from the pump 51 to the hydraulically loadable clamping means, hydraulic cylinders, 41. Thus, hydraulic fluid 41 flows to the hydraulic cylinders 41 on the piston side. As a result, the piston rods 42 of the hydraulic cylinders 41 extend until the counterforce acting on the piston rod compensates for the force exerted by the hydraulic pressure on the pistons. As in connection with FIG. 3 To recognize, this force corresponds to the clamping force acting on one of the axes 146, or the force which is applied as a clamping force on the two tension rollers of these axes of the chains. Conversely, when this force increases, the hydraulic pressure on the piston sides of the cylinders 41 increases. Then, the pressure regulating member opens a flow path leading back to a tank port 66 and thence to the tank 52, and from the hydraulic cylinders hydraulic fluid flows back into the tank. As a result, the piston rods are retracted again, until the clamping force of the chains has fallen back to a value corresponding to the hydraulic pressure setpoint. To It should be noted that the chain tension can fluctuate at a constant deflection of the hydraulic cylinders. This on the one hand due to the uneven rolling of a chain, according to the division of the chain. On the other hand, the pinching of a foreign body, as described above, make a short-term change in the deflection of the clamping device and thus also a hydraulic cylinder required. That is, the pressure regulating member 53 would have to readjust constantly short-term changes in the necessary for a particular chain tension center distance between the drive rollers and the idlers by continuously drained hydraulic fluid from the hydraulically actuated clamping means and this is fed back. On the one hand, this is associated with considerable hydraulic losses. On the other hand, there is also the risk of a dynamic swinging of the pressure regulating member. For this reason, a reflux limiter 54 is arranged in the hydraulic fluid flow path 61 between the pressure regulating member 53 and the hydraulically loadable clamping means 41. This is realized, for example, by a check member 55 and parallel to a throttle body 56 are arranged. The non-return member is arranged such that it opens in a flow direction from the pressure regulating member 53 to the hydraulically loadable clamping means 41 and allows unimpeded flow of the hydraulic fluid. In contrast, in a flow direction from the hydraulically loadable clamping means 41 to the pressure regulating member 53, the check member 55 closes, and the hydraulic fluid must flow through the throttle body 56. This means that hydraulic fluid can not flow back to the pressure regulating member 53 as fast as desired and be drained via this into the tank 52. With a slow increase in the force exerted by the tension rollers or the axis of the tensioning rollers on a hydraulically loadable clamping means, in this example, the force acting from the outside to the cylinder on the piston rods, the pistons can retract, wherein the case be discharged hydraulic fluid can be completely returned via the pressure regulating member 53 to the tank. On the other hand, in the case of rapid force increases, as they are caused by the aforementioned non-uniform rolling of a chain via a tensioning roller or the pinching of a foreign body, the return flow of the hydraulic fluid through the throttle element 56 is slowed down. It is still hydropneumatic accumulator 57 arranged. These are connected to a hydraulic fluid flow path between the Rückflussbegrenzer 54 and the hydraulically actuated clamping means 41. Hydraulic fluid, which is displaced from the hydraulically loadable clamping means upon a change in the deflection of the hydraulically loadable clamping means and can not flow off quickly enough via the reflux limiter 54, is temporarily stored in the pressure accumulators 57. In this case, the hydraulic pressure in the hydraulically loadable clamping means rises above the desired pressure value. If the hydraulically loadable clamping means are again loaded with a lower external force, then the hydraulic fluid cached in the pressure accumulators can again flow directly to the hydraulically loadable clamping means. Although this results in a possible short-term increase in the force applied by the hydraulically loadable clamping means clamping force, but on the other hand, the efficiency of the clamping device is increased, and the pressure regulating member must make fewer control operations with lower amplitude. Remains on the other side of the pressure in the hydraulically actuated clamping means over a longer period of time above the pressure setpoint predetermined pressure setpoint, the hydraulic fluid flows slowly and with a time delay via the throttle body 56 and the pressure regulating member 53 to the tank 52 back. In this sense, the throttle member 56 acts as a control element delay element 1st order at a reduction in the deflection of the clamping device. On the other hand, when the deflection of the tensioning device is increased, the necessary amount of hydraulic fluid can flow directly to the tensioning means 41 via the opened non-return member 55, so that the applied tensioning force does not fall below a value corresponding to the desired pressure value. A possible jumping off of the funding from the rollers is thus reliably avoided. By contrast, a temporary increase in the clamping force is tolerated and readjusted only by a time delay by reducing the deflection of the clamping device or the clamping means. It must be avoided, however, that the pressure in the clamping devices so far increases that it would cause mechanical damage. For this purpose, a return flow path 62 is provided by the clamping means to the tank, in which a pressure limiting member 58 is arranged. The passage the pressure limiting member 58 is closed at the target pressure set at the pressure regulating member 53. Only at a safety pressure, which is significantly above the target pressure, opens the pressure limiting member 58, such that the hydraulic fluid can flow freely from the clamping means to the tank. This ensures that a maximum permissible pressure in the clamping means 41 and a corresponding maximum permissible clamping force is not exceeded. At a setpoint pressure of, for example, 120 bar, the pressure limit value of the pressure-limiting element 58 is, for example, 250 bar in a specific, but by no means restrictive, embodiment. Parallel to the return flow path 62, a further flow path 63 is provided, in which a manually operable shut-off device 59 is arranged. This is closed during operation of the conveyor and allows a manual unloading of the clamping device, for example, during maintenance or inspection work, such as the exchange of funding. The illustrated hydraulic control device thus enables efficient and safe operation of the conveyor.

FIG. 5 shows another example of the execution of a scraper belt conveyor in a paver according to the teachings described herein. This essentially corresponds to the one in FIG. 3 given example, why is omitted to avoid repetition on a description of identical details. It is in this respect to the description of FIG. 3 directed. The in the FIG. 5 illustrated embodiment differs from that of FIG. 3 inasmuch as the tensioning device comprises elastic tensioning means 43 in addition to the hydraulically loadable tensioning means 41. The hydraulically actuated clamping means and the elastic clamping means are arranged in a series circuit. The elastic clamping means are connected at one end to the hydraulically actuated clamping means. In the illustrated embodiment, a coil spring is attached to one end of a piston rod 42, and is also pivotally connected to an axle 146. The coil springs can be made progressive. Of course, other types of elastic clamping means can be used, such as leaf springs, disc springs or elastomer packages. Likewise, in a tensioning device more elastic Clamping means can be arranged parallel to each other and in series with a hydraulically loadable clamping means. In conjunction with a hydraulic control device of the type described above, which reacts in a time-delayed manner to an increase in the force exerted externally on the hydraulically actuated clamping means, the elastic clamping means can compensate for small changes in the axial distances between the drive rollers 142 and the tensioning rollers 143, without that hydraulically acted clamping means must come into action, or with a limited deflection change of hydraulically acted clamping means. Longer-term changes in the deflection of the clamping device, however, are caused by the hydraulically actuated clamping means, and the elastic clamping means return to their original deflection. This in turn corresponds to a deflection which corresponds to that force which is predetermined by the pressure setpoint of the hydraulically loadable clamping means. Using series connected elastic clamping means with hydraulically loadable clamping means can on the pressure accumulator, which in conjunction with FIG. 4 have been omitted. Of course, it is also possible to provide both elastic clamping means and said pressure accumulator.

Although the subject matter of the present description has been explained with reference to selected exemplary embodiments, these are not intended to limit the claimed invention. The claims include embodiments that are not explicitly illustrated, and embodiments that depart from the examples shown are nevertheless covered by the claims.

LIST OF REFERENCE NUMBERS

1

Asphalt pavers

2

Direction of travel, working direction

10

tractor

11

drive

12

landing gear

13

Built-in waste bin, built-in bin

14

Scraper belt conveyor

15

hydraulic cylinders

16

hydraulic cylinders

17

Beam

20

Bohle

22

slug

23

masher

24

sliding plate

25

Frame, chassis

26

Linear guide member

31

Underground, Planum

32

mix

33

road surface

40

jig

41

Hydraulic cylinder, hydraulically acting clamping device

42

piston rod

43

Spring, elastic clamping device

50

Hydraulic control device

51

pump

52

tank

53

Pressure control element, pressure control element

54

Rückflussbegrenzer

55

return unit

56

throttle member

57

accumulator

58

Pressure relief body

59

manually operated shut-off device

61

Hydraulic fluid flow path

62

Return flow path

63

Hydraulic fluid flow path

65

Hydraulic fluid pressure connection

66

Tank connection, hydraulic fluid return connection

114

scratch tape

141

Chain

142

capstan

143

idler

144

plate

145

camp

146

axis

147

guide piece

148

drive shaft

149

pinion

214

scratch tape

1411

Chain

1412

Chain

1413

Chain

1414

Chain

F

conveying direction

Claims (15)

Conveying device (14) for a paver or feeder, comprising a revolving flexible conveyor (114, 214) and at least one tensioning device (40) for tensioning the conveyor, the conveyor being guided over at least two rollers, at least one of the rollers (142 ) is mounted stationarily to a frame (25), and at least one of the rollers is a tensioning roller (143) which is displaceable relative to the frame, the tensioning device being connected to the frame at a first end and to the frame at a second end Tensioning roller acts, wherein the clamping device comprises at least one hydraulically actuated clamping means (41). Conveyor device according to claim 1, wherein the tensioning device comprises at least one elastic tensioning means (43) and the hydraulically loadable tensioning means (41) and the elastic tensioning means (43) are arranged in a series connection. Conveying device according to one of the preceding claims, wherein .the hydraulically acted clamping means (41) is a hydraulic cylinder. Conveying device according to one of the preceding claims, wherein the tensioning device comprises a pressure accumulator (57). Conveying device according to one of the preceding claims, wherein the hydraulically loadable tensioning means is connected to a hydraulic control device (50), wherein in a hydraulic flow path (61) between a hydraulic pressure connection (65) and the tensioning means (41) a pressure control member (53 ) is arranged, which is provided and arranged to adjust the inlet pressure to the hydraulically actuated clamping means to a desired value. Conveying device according to the preceding claim, wherein the hydraulic control device comprises a Rückflussbegrenzer (54) which is arranged in a hydraulic flow path between the pressure control member (53) and the hydraulically actuated clamping means (41). Conveying device according to the preceding claim, wherein a pressure accumulator (57) is connected to a hydraulic flow path, which is arranged between the hydraulically acted clamping means (41) and the Rückflussbegrenzer (54). Conveying device according to one of the three preceding claims, wherein the hydraulic control device comprises a pressure limiting member (58) which is arranged in a return flow path (62), which leads from the hydraulically loadable clamping means to a tank connection, and whose pressure limit value is greater than the desired value of the inlet pressure is. Conveying device according to one of the preceding claims, wherein the conveying means comprises a link chain (141, 1411, 1412, 1413, 1414). Conveying device according to one of the preceding claims, wherein the conveying means is a scraper belt (114, 214). Conveying device according to one of the preceding claims, wherein the conveying device (14) is a conveying device for a paver (1), wherein the paver comprises mounting means (20), and wherein the conveying device is adapted and provided to remove material from a built-in bunker ( 13) of the paver to the installation means (20) to promote. A paver or feeder (1) comprising a conveyor (14) according to any one of the preceding claims, wherein the frame (25) is a chassis of the paver or feeder. Road paver or feeder (1) comprising a bunker (13) for built-in goods, and further comprising a conveying device (14) according to one of the preceding claims, which conveying device is adapted, provided and arranged to be built-in from the bunker (13) to a To promote discharge position of the paver or the feeder. Hydraulic control device (50) for a conveying device according to one of the preceding claims, wherein the control device is designed according to the features of one of the preceding claims relating to a hydraulic control device. A method for operating a conveyor (14), in particular in a paver or feeder, comprising a circulating flexible conveyor (114, 214) to provide and to guide over at least one tension roller and to apply a tension force to the tension roller to the conveyor under a voltage set, wherein the clamping force is applied by hydraulically acted clamping means (41).

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