CROSS REFERENCE TO RELATED APPLICATIONS

This application claims foreign priority benefits under 35 U.S.C. § 119(a)-(d) to European patent application number EP 22175359.3, filed May 25, 2022, which is incorporated by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to an insulating means to be connected with a screed for a road finishing machine, and to a combination of a screed and an insulating means.

BACKGROUND

Screeds are sufficiently well-known from prior art. They can be connected to a road finishing machine and supplied with material to be spread for the road pavement via a material bunker. The screed can further heat the material and distribute and press it on the road to be produced corresponding to the working width of the screed.

To be able to start the operation of a screed, the latter usually has to be preheated first to be brought to the required working temperature to reliably spread the material to be spread on the road at the adequate temperature. However, the screed has a large surface so that due to heat-conducting material as a component of the screed, a heat flow from the screed, and in particular the heating means of the screed, can reach the environment which can lead to an only delayed or at least energetically inefficient heating of the screed to the working temperature.

SUMMARY

Starting from the known prior art, a technical object to be achieved is to permit an energetically more efficient and/or less time-consuming heating of a screed for a road finishing machine.

According to the disclosure, this object is achieved by the insulating means to be used with a screed for a road finishing machine according to the disclosure, and the combination of a screed and an insulating means.

The insulating means according to the disclosure to be used with a screed for a road finishing machine comprises at least one insulating element and one connection element for a releasable connection with a screed, wherein the insulating element is designed to cause, in a state of the insulating means connected with a screed, a reduced emission of heat from a screed through the insulating element.

The connected state of the insulating means with the screed is here to be understood as a state wherein the insulating means is releasably connected with the screed by means of the connection element, so that at least the insulating element can carry out its intended function which is to reduce the emission of heat from the screed through the insulating element. This can also be understood as the “correct” positioning of the insulating means or at least the insulating element relative to the screed.

The insulating elements are here preferably fastened from the outside to the screed by means of a releasable connection, so that they can at least partially cover the outer surface of the screed.

A releasable connection is to be understood in the sense of this disclosure as a connection which can be created and released without destroying any material. Thus, the connection element is preferably designed as a connection element which can create a releasable connection with a corresponding connection element of a screed by creating a frictional connection or a friction contact. For example, the connection element can be configured as a plug or a clamp which can be engaged with a corresponding element of a screed.

According to the disclosure, a physical contact between the insulating element and the screed is not even compulsory in a connected state of the insulating means with the screed, but it can be provided. It is only necessary for the insulating element to be arranged relative to the screed in the connected state of the insulating means and the screed in such a manner that the quantity of heat emitted from the screed through the insulating element at least during a heating process of the screed to an operating temperature or working temperature can be reduced.

Thereby, the emission of heat to the environment is at least reduced during the heating of the screed which permits a quicker heating and/or a heating with lower energy consumption. The heating of a screed can thus be rendered more advantageous with respect to ecological, but also economical points of view since less energy has to be consumed for reaching the required operating temperature.

Upon completion of the heating of the screed, the insulating means can be released from the screed to take up the operation of the screed. As an alternative, the insulating means can also be maintained connected to the screed, for example to reduce the emission of heat to the environment also during operation.

In particular, the insulating means and/or at least one insulating element that can be positioned at or in the region of the bottom side or standing side of the screed can have a high coefficient of static friction and/or a high coefficient of kinetic friction. In particular, the coefficient of static friction and/or the coefficient of kinetic friction of the insulating element can preferably be greater than the corresponding coefficient of the screed. To this end, the insulating element can consist of a material having such a coefficient of static friction and/or coefficient of kinetic friction, or comprise an outer coating of such a material on a surface facing away from the screed in the state connected with the screed. Thereby, in addition to the improved heating, a secure positioning of the screed can be effected in a constructively simple manner. In particular, this anti-slip property of the insulating element or the insulating means can be advantageously utilized to securely position, for example, the screed during transport with a truck.

Furthermore, the insulating element can comprise an insulating material, optionally on a surface facing the screed or facing away from the screed in a state of the insulating means connected with the screed.

The insulating material can either be integrated in the insulating element itself, or it can be arranged on the surface facing the screed or away from it so that the heat conduction through the insulating element is reduced compared with the heat conduction to the environment without the insulating element. The insulating element can be designed as a “blanket” or a “mat” which preferably includes a surface facing, in the connected state of the insulating means with the screed, and a surface facing away from it which together cover at least 80% or at least 90% of the total surface of the insulating element. By the large surface parallel to the surface of the screed, the reduction of the quantity of heat emitted by the screed into the environment can be effected efficiently.

Advantageously, the insulating material can comprise one of rubber, polyurethane, composite foam, or consist thereof. These materials have a low coefficient of thermal conductivity, so that the insulation of the screed is as efficient as possible. Basically, the embodiments described herein are not to be understood as restricting. Any material or any combination of materials can be used for the insulating material which has a coefficient of thermal conductivity preferably reduced with respect to the material of the screed.

In one embodiment, the insulating means comprises an active heating element for heating a screed in a state of the insulating means connected with the screed. An active heating element is to be understood as an element that, when energy (for example current) is supplied, converts this energy substantially (preferably at least 90%) into heat and can emit this heat. With this embodiment, the insulating means can additionally contribute to the heating of the screed which can cause the reaching of the intended working temperature more quickly. Though energy is necessary for this, the required time for reaching the working temperature is reduced thereby, so that the operation of the screed can be rendered more efficient.

In particular, the active heating element can be integrated in the insulating element or be arranged on a side of the insulating element facing the screed in a state of the insulating means connected with the screed. With this embodiment, a reduction of the emission of heat from the screed to the environment through the insulating element can be simultaneously caused, and additionally, an efficient heating by means of the active heating element of the insulating means can be effected which at least reduces the time for reaching the operating temperature of the screed.

The active heating element can also comprise an electric heating element, and the insulating means can comprise an accumulator which can be connected with the active heating element for supplying current to the active heating element.

With this embodiment, the insulating means does not require a lot of maintenance and is broadly applicable, whereby its use can in particular be easily realized even by single builders.

In one embodiment, the insulating element can reduce the emission of heat from a screed through the insulating element by at least 25% or at least 50% or at least 75%. This reduction is to be understood relative to the emission of heat of the screed to the environment without any insulating element. At least in the region of the insulating element, the heat loss during the heating of the screed is thereby effectively reduced.

Furthermore, the connection element can be designed as part of a security system for enabling a heating process of the screed only in a state of the screed connected with the insulating means.

Thus, the connection element can perform a double function by, on the one hand, serving the correct positioning and/or connection of the insulating means with the screed, and on the other hand, creating an electric contact, for example, which can, for example, emit a signal to a control unit of the screed indicating that the connection has been created. The control unit can then enable the heating of the screed. The putting into operation of the screed, and in particular the starting of the heating process, can thus only be effected if the insulating means is correctly connected with the screed. Thereby, an unintentional heating of the screed without the insulating means, and thereby an energetically less efficient heating of the screed, can be avoided.

In one embodiment, the insulating means comprises at least two insulating elements. Basically, the insulating elements can have the same design (for example in view of shape and/or size and/or weight), but they can also differ with respect to their shape and/or size and/or weight. The provision of a plurality of insulating elements can be advantageous to facilitate a handling of the insulating means even by single operators.

In particular, each insulating element can weigh less than 20 kg, preferably less than 10 kg. By the embodiment of the insulating elements with these maximum weights, a manual handling by one single worker or the operator of a screed or a road finishing machine can be realized which increases the applicability of the insulating means.

According to the disclosure, furthermore a combination of a screed and an insulating means according to one of the previous embodiments is provided, wherein the insulating element is arranged at least at a portion of a surface of the screed, and wherein the screed comprises a heating means for heating the screed.

With this combination, an efficient heating of the screed can be realized.

The screed can also comprise a security system which only enables an activation of the heating means if the connection element of the insulating means is connected with the security system of the screed. A putting into operation or a heating of the screed by means of the heating means without a (correctly positioned) insulating means is prevented with this embodiment, thus avoiding an inefficient heating of the screed.

In one embodiment, the insulating means comprises at least two insulating elements, and the insulating elements together cover at least 50% of the surface of the screed. Thereby, the heat loss during the heating of the screed can be efficiently reduced. Particularly preferred, the largest individual surface elements of the screed can be covered by insulating elements of the insulating means, so that no heat can escape through them.

DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically shows a screed of a road finishing machine and an insulating means connected thereto according to one embodiment; and

FIGS. 2A-2D show different embodiments of an insulating element and the insulating means.

DETAILED DESCRIPTION

FIG. 1 shows a schematic view of a screed 110 of a road finishing machine 120 and an insulating means 100 arranged relative to the screed 110 according to an embodiment.

As is known from prior art, a screed 110 for producing a road pavement can usually comprise a heating means 112 (e.g., one or more electrical resistance heating elements such as coils or rods, one or more gas heating elements such as gas burners, or any other suitable heating element or elements) as well as a screed plate 111 which is heated by the heating means 112 and heats and can press on a road pavement spread below the screed plate. The screed 110 can be connected to the traction vehicle 120 or the “road finishing machine” by connection elements 113, such as tow arms and/or leveling cylinders. If the connection elements 113 are designed as leveling cylinders, by a corresponding activation and actuation of these leveling cylinders, for example by means of a controlling system 180, any ground irregularities can be compensated. The levelling cylinders can also be designed passively and thus at least partially follow the course of the subsoil during the finishing of the road pavement while they ensure a required press-on pressure of the road pavement.

Instead of one single heating means 112, a plurality of heating elements can also form the heating means which are then distributed at different positions in the screed 110 to cause a heating of the screed plate. Basically, the heating means 112 can produce heat, for example, by means of electric current, and emit it to the screed plate 111 to heat the latter.

It is also known from prior art that the screed 110 first has to undergo a heating phase in which the screed plate 111 (and optionally the complete screed 110) is heated to a required operating temperature. Only when this operating temperature is reached, the screed can be employed for finishing a road pavement. During this heating phase, the heating means 112 of the screed is used to cause the heating of the screed plate 111. When the operating temperature is reached, the heating means 112 can still emit heat to keep the temperature of the screed plate constant.

During the heating phase, comparably much energy is required, and, since the screed is usually formed of thermally well-conducting materials (for example steel) or comprises the same, quite a considerable heat flow from the screed to the environment occurs, so that a portion of the heat emitted from the heating means is finally not available for heating the screed plate 11 or the screed, but dissipates into the environment.

According to the disclosure, an insulating means 100 that can be releasably connected to the screed 110 is therefore provided, which comprises at least one insulating element 101 (e.g., heat insulating plate, heat insulating layer, etc.) which, insofar as the insulating means is in a state connected with the screed, can reduce an emission of heat from the screed to the environment at least in the region of the insulating element. To this end, the insulating element 101 of the insulating means 100 can, as represented here, for example be positioned below the screed 110 (that means between the screed and ground), so that the screed plate to be heated by the heating means 112, or another part of the screed, emits heat at least partially towards the insulating element.

Due to the heat-insulating properties of the insulating element, a transfer of the heat to the environment through the insulating element is prevented, or at least partially prevented, so that this heat is not dissipated into the environment but is available for heating the screed.

The embodiment of the insulating means with only one insulating element is not compulsory. The insulating means 100 can also comprise more than one insulating element 101 (e.g., heat insulating plate, heat insulating layer, etc.), and in particular, the insulating elements can also be arranged at other surfaces of the screed 110, so that, in the connected state of the insulating means and the screed, a heat flow from the screed through the insulating elements to the environment is reduced or completely prevented.

The insulating means 100 preferably has a connection element 102 for releasably connecting the insulating means, or at least one insulating element 101 of the insulating means, with the screed 110. For example, the connection element 102 can be realized as a click connection or a threaded connection or a clamp or another releasable connection element (e.g., one or more pins, screws, bolts, clamps, etc.), so that the connection element 102 can be connected, for example, with a corresponding connection element 103 (e.g., one or more receptacles, openings (such as threaded openings), projections, tabs, etc.) of the screed 110 to create the releasable connection. In general, this releasable connection can be realized by a friction contact and/or an interlocking contact. Preferably, the connection elements 102 and 103 can be designed such that a creation of the connection between the connection elements 102 and 103 is only possible in a position of the insulating means and/or the insulating element 101 in which the insulating element is positioned correctly relative to the screed 110. This ensures that, when the screed is put into operation and in particular the heating process is performed, the insulating elements or the insulating element 101 realize the intended function, and the emission of heat through them is reduced.

The connection element 102 of the insulating means 100 can also form a part of a security system 131, which may also include, for example, a sensor or sensor assembly and a controller (e.g., control unit 180), and which only permits to enable the heating process of the screed 110 (that means in particular an activation of the heating element 112) if the connection between the connection element 102 of the insulating means 100 and the corresponding connection element 103 of the screed 110 has been created. To this end, for example, an electric or electronic contact can be provided that is closed when the connection elements 102 and 103 are connected, and/or connection between the connection elements 102 and 103 may be detected by the sensor or sensor assembly, so that, for example, the control unit 180 receives a corresponding signal and subsequently enables the putting into operation of the heating element 112.

FIGS. 2A-2D show various embodiments of an insulating element of FIG. 1 as can be provided as part of the insulating means according to the disclosure.

While only one insulating element is shown both in FIG. 1 and in FIGS. 2A-2D, the insulating means 100 can, as already mentioned, comprise a plurality of insulating elements which can also be positioned at various positions relative to the screed to prevent or reduce heat emission through them. Here, the insulating elements can preferably be designed such that they can be handled by one single operator or worker, for example the operator of a road finishing machine 120 to which the screed 110 is connected. In particular, each insulating element can have a mass of less than 20 kg, preferably less than 10 kg. In particular in the embodiment with a mass of less than 10 kg, the handling by one single person is comparably easily possible.

Basically, and independent of the embodiments described in detail with reference to FIGS. 2A-2D, it is also advantageous if the heat emission through the screed reduced by each insulating element would be at least 25%, preferably at least 50%, or at least 75%, at least in the region of this insulating element, compared to the heat emission that would occur through the screed in this region to the environment without any insulating element.

In FIG. 2A, now a first embodiment of an insulating element 201 is represented which consists of two layers 211 and 212. For a better understanding, it is assumed that the upper side of the layer 211, which faces away from the lower layer 212, faces, in a state of the insulating means connected with the screed, in the direction of the screed or contacts it, that means that the bottom side of the layer 212 not represented in this picture faces, as the outer surface of the insulating element, away from the screed in the connected state of the insulating means with the screed.

Corresponding to the embodiment represented in FIG. 2A, the upper layer 212, or at least the surface facing in the direction of the screed, can comprise an insulating material, or the lower layer 212 can comprise an insulating material (respectively the surface of the layer 212 facing away from the screed). The layer 211 or the layer 212 or their surfaces can also completely consist of the insulating material. Preferably, the insulating material can be, for example, rubber, polyurethane, or a composite foam. Preferably, for the insulating material, materials are used whose thermal conductivity is smaller than 0.5 W/(mK), preferably smaller than 0.3 W/(mK).

While in FIG. 2A, the insulating element 201 is composed of two layers, wherein one of them or even both can comprise the respective insulating material, one of the two layers can also completely consist of the insulating material. Thus, the layer 211 can be considered, for example, as a “surface” of the layer 212 and consist of the insulating material. As an alternative, the layer 212 can be considered as consisting of the insulating material and forming the surface of the layer 211.

The respective other layer which does not comprise the insulating material can act as a support layer to stabilize the insulating element and can have, for example, an increased stiffness compared to the insulating material. This can facilitate the handling.

The shape of the insulating element shown in FIG. 2A, but also in the other FIGS. 2B-2D, is not compulsory. The shape of the insulating elements or the insulating element of the insulating means can basically be arbitrary. However, shapes are preferred that are easily handable, such as rectangles or squares, since they can be placed one next to the other without any gaps to achieve a preferably complete and continuous insulation of the screed.

In FIG. 2B, an embodiment as an alternative to FIG. 2A is represented wherein the insulating material 222 in this embodiment is arranged between two layers 223 and 221 which can consist of another material, and wherein these three layers together form the insulating element 202. The layers 221 and 223 can here take over functions not relevant for the heat conduction from the screed through the insulating element 202 and can serve, for example, as support layers for the insulating material 222. Moreover, the layer 221 arranged on the side of the insulating material 222 facing away from the screed in the connected state of the insulating means with the screed can consist of a material that reflects infrared radiation or comprise a corresponding surface (for example of an aluminum foil). It can be arranged on the surface of the layer 222 facing in the direction of the insulating material 222 so that, if a heat transport is effected by infrared radiation here, the latter is reflected and does not leave the insulating element 202 in the direction of the environment.

While the embodiments of FIGS. 2A and 2B have been described as multilayer systems, a realization with only one material layer is also possible. For example, one single layer of the insulating material can be provided as the insulating element. This layer can preferably comprise a material that reflects infrared radiation on the surface facing away from the screed to prevent an emission of heat by infrared radiation.

FIG. 2C shows a further embodiment of an insulating element 203 in which the insulating element comprises an active heating element 233 which can be designed, in the embodiment represented herein, for example as comprising a row of heating coils. Other embodiments are also conceivable, such as any other suitable electrical resistance heating element or elements (e.g., one or more rods), or one or more gas heating elements (e.g., gas burners), or any other suitable heating element or elements. Preferably, the active heating element 233 is arranged in the insulating element 203 such that it is arranged on a side of the insulating element facing the screed in a connected state of the insulating means and the screed, which can be understood here as the “upper side”. Here, it can be arranged on the surface of a material layer 231 particularly suited for this which can be arranged on a further material layer 232 of the insulating element 203 which, for example, comprises a material with a lower thermal conductivity or consists thereof. The material layer 231 can be thermally particularly well conductive to cause a transfer of the heat from the active heating element 233 to the screed. The material layer 232 can then consist of an insulating material as described above or comprise the same to prevent or reduce a heat conduction in the direction away from the screed. As an alternative or in addition, analogously to FIG. 2B, a surface coating that reflects infrared radiation can be provided in or on the layer 232 in order to reflect the heat radiation—that is emitted by the active heating element 233 in a direction away from the screed in a connected state of the insulating means and the screed—in the direction of the screed, so that the heat emitted by the active heating element 233 is preferably completely utilized for heating the screed.

Moreover, an accumulator 234 can be associated with the active heating element which is connected or can be connected with the active heating element for supplying current to the active heating element. This accumulator 234 can be designed, for example, as a battery or a rechargeable battery or a fuel cell and be connected with the active heating element 233 via corresponding current-carrying lines. As an alternative, instead of an accumulator, a connection to a (publicly available) electricity supply grid or to a combustion engine, for example to the combustion engine of the road finishing machine, can be provided.

In FIG. 2D, a further embodiment is represented in which the active heating element 243 (e.g., one or more heating coils or rods, or any other suitable heating element or elements) is embedded in the material layer 241 and not, as is represented in FIG. 2C, arranged on the surface of this material layer 231 of the insulating element 203. By the embedding into a material layer 241, which preferably has a good thermal conduction (in particular has a better thermal conduction than the insulating material), on the one hand, a uniform heat distribution of the heat emitted by the active heating element 243 in the direction of the screed can be effected, and on the other hand, a protection of the active heating element 243 from environmental influences (for example humidity) can be realized. Analogously to FIG. 2C, here, too, a corresponding accumulator 244 can be provided.

The layer 242 of the insulating element 204 in FIG. 2D can be formed analogously to the layer 232.

As those skilled in the art will understand, the control unit 180, as well as any other controller, unit, component, module, system (e.g., security system 131), subsystem, sensor, sensor assembly, element, device, or the like described herein may individually, collectively, or in any combination comprise appropriate circuitry, such as one or more appropriately programmed processors (e.g., one or more microprocessors including central processing units (CPU)) and associated memory, which may include stored operating system software, firmware, and/or application software executable by the processor(s) for controlling operation thereof and for performing the particular algorithm or algorithms represented by the various methods, steps, functions and/or operations described herein, including interaction between and/or cooperation with each other. One or more of such processors, as well as other circuitry and/or hardware, may be included in a single Application-Specific Integrated Circuit (ASIC), or several processors and various circuitry and/or hardware may be distributed among several separate components, whether individually packaged or assembled into a System-on-a-Chip (SoC).