Method of heating screed of road finishing machine

Abstract

To constitute a screed of a road finishing machine with further simply and / or acceptably in the view of environmental protection.SOLUTION: The method includes obtaining a prescribed time to operate a screed, obtaining a start time to start heating of the screed on the basis of the prescribed time, and automatically heating the screed from the start time by energy supply from an energy source to heating means of the screed. The steps of obtaining the prescribed time and the start time and controlling automatic heating can be executed basically by a control unit associated with the screed or inclusively by a (central) control unit of a road finishing machine.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for heating the screed of a road finishing machine as described in claim 1, and to a road finishing machine comprising a screed and a control unit corresponding to independent claim 10. [Background technology]

[0002] Road finishing machines are well known from the prior art. They typically include a screed that receives material for road paving to be applied from a material bunker of the road finishing machine, or a material bunker associated with the road finishing machine, and spreads this material onto the subsoil where the road paving is to be laid. For this purpose, the screed typically includes one or more heating means for heating the material, or for maintaining the material at a given temperature while the material is being spread on the subsoil, so that the road paving can be spread and pressed properly.

[0003] For this reason, the screed must be heated to working temperature before the road finishing machine is put into operation, so that the material to be spread can be reliably heated to the desired temperature. This requires that the road finishing machine be operated at least partially before actual work involving the road finishing, in which the material for producing the road pavement is spread, can begin.

[0004] This requires precise work planning at construction sites, taking into account changing circumstances, which is a challenge not only for road finishing machine operators but also from economic and environmental protection perspectives. [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] Therefore, starting with known prior art, the technical challenge to be solved is to configure the heating of the screed of a road finishing machine to be simpler and / or more environmentally acceptable. [Means for solving the problem]

[0006] According to the present invention, this objective is achieved by a method for heating the screed of a road finishing machine as described in independent clause 1, and by a road finishing machine comprising a screed and a control unit, corresponding to independent clause 10. Further advantageous developments of the present invention are included in the dependent clauses.

[0007] The method for heating the screed of a road finishing machine according to the present invention is: A step to obtain a predetermined time for operating the screed, A step of obtaining a start time to begin heating the screed based on a predetermined time, The method includes the step of automatically heating the screed from a start time by supplying energy from an energy source to a means for heating the screed.

[0008] The steps of obtaining the predetermined time and start time, as well as controlling the automatic heating, can be carried out basically by a control unit associated with the screed, or more broadly, by the (central) control unit of the road finishing machine. The control unit can be configured in particular as a computer.

[0009] In particular, a predetermined time for operating the screed can be supplied to the control unit via input from the operator, and the control unit can then determine, through further internal processing, the start time for beginning to heat the screed. Here, other parameters related to the operation of the screed, or environmental parameters, may be taken into consideration. The predetermined time should be understood here as the time at which the operation of the road finishing machine or the screed can be started, respectively. This means that, upon reaching the predetermined time, the screed is preferably heated to the working temperature required for the normal operation of the screed.

[0010] The energy supply from the energy source can be defined in particular as the supply of electric current to the heating means.

[0011] According to the present invention, the start time of heating is until a predetermined operating time, and is selected in particular so that the heating of the screed is just completed when the predetermined operating time for the screed has been reached.

[0012] This should be understood to mean that the start time is determined based on a predetermined time such that the distance between the start time and the predetermined time is just long enough for the screed to be automatically heated from its original temperature at the start time to a target or working temperature reached at a predetermined time, according to selected parameters for heating the screed. It can also be provided that the start time is selected so that the target or working temperature of the screed is reached within a period of approximately ±10 minutes, ±15 minutes, or ±30 minutes of the predetermined time.

[0013] In a preferred embodiment, the method according to the present invention preferably allows the screed to heat up such that the time interval during which the screed is operating at a desired working temperature is preferably short, even though the screed is not actually operating (meaning spreading material on the subsoil to produce road pavement). Preferably, the screed reaches working temperature in a maximum of 20 minutes, preferably a maximum of 10 minutes, before a predetermined time. If the start time is selected so that the working temperature is reached within a certain period before a predetermined time (e.g., 20 minutes or 10 minutes), this can also act as a time buffer to offset, for example, changing environmental conditions that would adversely affect the time required for the screed to heat up (e.g., sudden rain within the time interval between the start time and the predetermined time), and to ensure that the working temperature is reached by the time the predetermined time is reached.

[0014] As a result, energy is saved, making this method more environmentally friendly and / or economically acceptable.

[0015] Therefore, since pre-planning of heating is no longer required by the operator, the operation of the screed can be made easier for the operator.

[0016] It may be further provided that the energy source is an accumulator connected to the main drive unit of the road finishing machine, or a fuel cell connected to the main drive unit of the road finishing machine, or an external energy source connected to the main drive unit of the road finishing machine or the road finishing machine, or includes these.

[0017] In particular, in embodiments of road finishing machines as electric or hybrid driven vehicles, or fuel cell vehicles, it is possible to provide that the connection between the screed and an energy source for energy supply (meaning an accumulator or fuel cell) can be achieved without operating the main drive unit. This means that energy is directly utilized from the fuel cell or accumulator as electrical energy to warm up or heat the screed, without energy being additionally consumed by the main drive unit of the road finishing machine which is not being used at this time. Since the conversion of energy stored in such an energy source is possible without operating the main drive unit, these embodiments are particularly advantageous from an environmental and / or economic standpoint. As an external energy source, for example, a connection to an available public power grid for the screed or the means of heating the screed can be used.

[0018] In one embodiment, obtaining the start time is further achieved based on measured environmental parameters. These environmental parameters may, in particular, include at least one of ambient temperature, humidity, precipitation per unit time, and brightness.

[0019] In the case of these embodiments, environmental influences that may have a bad or good effect on the time interval required to heat the screed can be taken into account in the determination of a given time. For example, if the ambient temperature is relatively high (e.g., above 25 °C or above 30 °C), less energy and / or a shorter time is required to heat the screed, whereby the start time can be determined at a shorter time distance relative to the given time. If the ambient temperature is lower (e.g., only 10 °C or less than 0 °C), a longer time is required to heat the screed, whereby the distance between the start time and the given time can be correspondingly selected to be longer or must be selected.

[0020] The environmental parameters can be measured by corresponding sensors that can be connected to the screed and / or the road finisher. For example, humidity sensors, rain sensors and / or temperature sensors (e.g., in the form of an electronic thermometer), which are basically known as such, can be used.

[0021] Furthermore, obtaining the start time can be done based on the measured cooling parameters and / or heating parameters of the screed.

[0022] This embodiment can be combined with the aforementioned embodiments regarding obtaining the start time based on the measured environmental parameters, but can also be provided as an alternative to these embodiments.

[0023] The cooling parameters and / or heating parameters can preferably be a single number or a single value, by which, for example, parameters characterizing the heat transfer from the screed to the environment can be aggregated not only for the cooling behavior but also for the behavior when taking in heat, and thus generally for determining the warming behavior of the screed. In the case of this embodiment, the behavior of the screed can be taken into account for the determination of the start time that can reliably ensure the heating of the screed up to a given time.

[0024] In particular, the measured cooling parameter can be determined by heating the screed to a predetermined test temperature and subsequently determining the parameter associated with the cooling of the screed, and / or the measured heating parameter can be determined by heating the screed to a predetermined test temperature and subsequently determining the parameter associated with the heating of the screed. By this method, the cooling parameter and / or the heating parameter can be determined technically easily. Further, with a single heating to the test temperature, both parameters can be determined in this way, which can minimize the occurrence of systematic errors and / or probabilistic errors when determining the cooling parameter and / or the heating parameter.

[0025] In one embodiment, the automatic heating is actuated by the control unit of the screed only when the control unit receives a signal indicating the positioning of the protective element. The control unit can be a separate control unit (e.g., a computer) associated only with the screed. However, the control unit can also be the control unit of the road finishing machine.

[0026] Thereby, even when the operator is absent, it can be ensured that the environmental conditions for heating the screed meet specific requirements, for example, that the screed is horizontal or that the screed is shielded from the environment by a non-combustible material. This improves operational safety.

[0027] In particular, it can be provided that the protective element includes a non-combustible material and / or a heat-insulating material. The use of a non-combustible material, particularly a heat-insulating material, under or around the screed can respectively achieve a safer and simultaneous, or alternatively, more environmentally friendly and economically acceptable warm-up or heating of the screed.

[0028] It can be further provided that obtaining a predetermined time is achieved based on inputs to the operating elements of the road finishing machine and / or based on inputs from input means connected wirelessly to the screed's control unit. The user can communicate a predetermined time to the road finishing machine or its control unit, particularly via an application on a mobile device such as a smartphone, and via a wireless connection such as mobile internet (4G, LTE, etc.), thereby allowing the control unit to determine a start time based on that. This enables the operator to easily control the screed.

[0029] The road finishing machine according to the present invention comprises a screed and a control unit, the screed and control unit being configured to perform a method of heating the screed, the method being, Obtaining a predetermined amount of time to operate the screed, Based on a predetermined time, the start time for starting the heating of the screed is obtained, This includes automatically heating the screed from a start time by supplying energy from an energy source to a means for heating the screed.

[0030] This road finishing machine can achieve more economically and / or environmentally acceptable heating of the screed, while simultaneously increasing ease of operation for the operator.

[0031] It may be further provided that the energy source is an accumulator connected to the main drive unit of the road finishing machine, or a fuel cell connected to the main drive unit of the road finishing machine, or an external energy source connected to the main drive unit of the road finishing machine or the road finishing machine, or includes these. The use of an accumulator or fuel cell makes it possible to supply energy to the heating means (e.g., electric current) without the main drive unit needing to be operated, which can also make the heating of the screed more efficient from an economic and / or environmental standpoint.

[0032] In one embodiment, the road finishing machine is equipped with sensors for measuring environmental parameters, and the control unit is configured to determine the start time based on the measured environmental parameters. The determination of the start time can therefore be performed more reliably, which may be advantageous considering economic and / or environmental protection factors.

[0033] Furthermore, the control unit can be configured to determine the start time based on the screed cooling parameters stored in the control unit's memory. This allows the thermal behavior of the screed to be taken into account, enabling more energy-efficient heating of the screed.

[0034] In one embodiment, the control unit is configured to activate screed heating only when it receives a signal indicating the positioning of a protective element. The protective element may include, in particular, non-combustible and / or insulating materials. Thereafter, screed heating can be performed in an energetically favorable manner and, at the same time, designed to be safer. [Brief explanation of the drawing]

[0035] [Figure 1] Figure 1 is a schematic diagram of a road finishing machine having a screed according to one embodiment. [Figure 2] Figure 2 is a flowchart illustrating a method for heating the screed of a road finishing machine according to one embodiment. [Figure 3] Figure 3 is a flowchart illustrating a method for determining the cooling parameters of a screed according to one embodiment. [Modes for carrying out the invention]

[0036] Figure 1 shows a road finishing machine 100 having a screed 110 according to one embodiment of the present invention. As is known, the road finishing machine 100 comprises a towing vehicle 120 or automobile 120 to which the screed 110 is connected. The screed 110 can be connected to the towing vehicle 120, for example, via a connecting element 113 presented herein, which can be specifically designed as a leveling cylinder to compensate for unevenness in the subsoil when the road pavement is widened by the screed 110. However, the connecting element 113 can also be designed as a rigid connecting element.

[0037] The towing vehicle 120 is typically equipped with a main drive unit 140. This main drive unit can be designed, for example, as a combustion engine (diesel engine or gasoline engine). In an alternative preferred embodiment, the main drive unit 140 may be an electric motor, a hybrid drive unit, or a fuel cell drive unit.

[0038] In the case of an electric or hybrid main drive unit or fuel cell drive unit 140, an "energy source" 141 in the form of an accumulator or fuel cell 141 can be connected to and provided with the main drive unit 140, thereby allowing energy to be transferred, for example, from the accumulator or fuel cell to the main drive unit. In the case of an accumulator, this is electrical energy, which can then power the electric motor of an electrically driven road finishing machine 100, or the electric motor of a hybrid-driven road finishing machine 100, as the main drive unit 140.

[0039] If the main drive unit is designed as a combustion engine, the energy source can be designed as a fuel tank (e.g., gasoline or diesel).

[0040] An energy source in the form of a fuel cell and / or accumulator 141 can be provided to be connected to a heating means 112 of the screed 110 independently of the connection between the energy source and the main drive unit 140, thereby allowing the heating means 112 of the screed 110 to be supplied with energy, preferably without operating the main drive unit 140 or supplying energy to the main drive unit 140. Alternatively, the heating means of the screed can be connected only to the main drive unit 140, thereby supplying energy to the heating means of the screed via the operation of the main drive unit.

[0041] The heating means 112 can be used to heat and operate the screed 110. For this purpose, the screed 110 can first be heated by the heating means 112 to a desired temperature (which is also the operating temperature hereafter as specified herein). This may include, in particular, heating the screed plate 111 of the screed 110. As is known, the screed plate 111 is used to uniformly distribute a road pavement spread onto the subsoil by pressing and heating it and applying it onto the subsoil. The heating means can heat this screed plate, but further components of the screed can also be heated to a desired operating temperature.

[0042] Here, it can be provided that a control unit 180 (for example, in the form of a computer) is associated with the screed 110 and / or the road finishing machine 100. The control unit 180 may have a data memory 181 or be associated with the memory 181. For example, this memory 181 may be designed as an internal hard disk of a computer that implements the control unit 180. Alternatively or in addition, the memory 181 may be implemented in the form of (variable) non-volatile memory (e.g., a USB stick). Furthermore, an operating element 182 in the form of a keyboard, touchscreen, or mobile terminal (e.g., a smartphone), connected to the control unit via a wireless connection, may be associated with the control unit 180, through which an operator of the control unit can input information.

[0043] In embodiments presented herein, protective elements 130 are further shown. These protective elements may be designed as non-combustible and / or insulating elements, or both, or may include such elements and be positioned, for example, beneath the screed, or (for example, when designed as multiple mats) preferably completely enclose the screed, covering, for example, at least 50% or at least 80% of the outer surface of the screed. This prevents ignition of the screed and the environment, particularly during heating of the screed, thereby minimizing the risk of accidents.

[0044] If insulating material is further used in the protective element(s) 130, heat dissipation from the screed to the environment through at least the protective element(s) 130 can be reduced or avoided during heating of at least the screed 110, which could reduce the energy efficiency during heating of the screed over the time required to heat the screed. Possible elements here include, for example, elements with a low thermal conductivity coefficient, such as rubber, polyurethane, or foamed material. However, embodiments are not limited to these materials. Basically, any material or combination of materials having insulating properties and preferably a lower thermal conductivity coefficient than the material of the screed can be used. Therefore, layered structures including, for example, ceramics and further materials can also be used.

[0045] In one embodiment, a control unit 180, as described below herein, may be provided to perform screed heating only when the protective element(s) 130 are correctly positioned. To ensure this, a safety switch 130 may be provided to be automatically and / or (manually) closed only when the protective element(s) 130 are correctly positioned. The safety switch 131 may be designed as an electrical or electronic switch that closes, for example, when the protective element(s) 130 are correctly positioned relative to the screed 110 (for example, by the connection of the protective element(s) 130 to the connecting element(s) of the screed. At this point, the element(s) 131 can transmit a corresponding electrical or electronic signal to the control unit 180, which can then activate screed heating based on this signal indicating the correct positioning of the protective element(s) 133 relative to the screed 110. Heating can then be triggered in accordance with the following embodiments.

[0046] The road finishing machine may further include at least one sensor 190 that measures one or more environmental parameters. The sensor 190 may be designed to measure, for example, ambient humidity, precipitation (rain or snow), brightness, and / or temperature.

[0047] Figure 2 shows a flowchart of a method for heating a screed according to one embodiment.

[0048] Method 200, corresponding to Figure 2, begins in a first step 201, where the control unit 180 obtains a predetermined time for the screed to be heated to a desired temperature or for the screed to be finally operated. Obtaining this predetermined time in step 201 can also be repeated, for example, based on a time switch. For example, an operator can once communicate to the control unit that the screed should be heated to a desired operating temperature and operated at a specific time on a specific day. For example, the control unit may include information stored in memory 181, according to which the screed must be operational at 8:00 each weekday from Monday to Friday, meaning in particular that the screed must be heated to its operating temperature. This means that the heating of the screed must already be completed by this time.

[0049] Alternatively or in addition, it may also be provided that the screed operator can input a predetermined time to the control unit, for example, by input via an operating element 182 associated with the control unit (e.g., a keyboard).

[0050] Alternatively, or in addition, the control unit 180 may also receive a predetermined amount of time, for example, through the input of corresponding information on a mobile terminal, particularly a smartphone, as an operating element 182. In this case, a corresponding application, or "app," can be stored on the mobile terminal (meaning, for example, a smartphone) 182, which enables remote access to the road finishing machine's control unit 180. This access can be achieved, for example, via an encrypted connection (such as a VPN connection), thereby preventing unauthorized access to the road finishing machine's control unit 180.

[0051] Furthermore, as an alternative or in addition, the control unit may obtain a predetermined time from a construction site management system associated with the road finishing machine or otherwise integrated into the control unit 180. In the construction site management system, for example, information regarding the planned arrival of trucks carrying the covering material may be stored at the construction site or the road finishing machine, or retrieved through it. The control unit can then obtain, for example, a predetermined time as the planned arrival time of the next truck carrying the covering material.

[0052] After a predetermined time has been obtained in step 201, the control unit may, in step 202, determine a start time for starting the heating of the screed based on the predetermined time obtained in step 201. In one embodiment, this may include the start time always being set at a predetermined time interval prior to the predetermined time. Thus, the control unit may, for example, automatically determine the start time 30 minutes before the predetermined time based on information stored in memory 181. At this point, the heating of the screed can then be started, thereby bringing the screed to a desired operating temperature, for example, until a predetermined time is reached.

[0053] In other embodiments, additional information 221 is also used in step 202 to determine the start time. This additional information can be obtained, for example, via a sensor 190 on the road finishing machine. The sensor can measure temperature and / or humidity and / or precipitation and / or brightness, and from these environmental parameters, the start time can also be determined considering a predetermined time. For example, if the ambient temperature is relatively high (e.g., above 30°C), the screed heating can be started later (not so far from the predetermined time) than in the case of an ambient temperature of -3°C. Furthermore, information on humidity and / or precipitation and brightness can be used to determine the start time, additionally considering these environmental parameters based on a predetermined time.

[0054] Furthermore, as already explained regarding obtaining a predetermined time, information from the construction site management system can be used to reach the start time. Thus, the construction site management system may have weather information for the time at that moment and / or for future periods. The start time can be determined based on the weather (perhaps) predicted for a predetermined time (e.g., the morning of the next day when the screed must be operated again) and / or for the period preceding this, for example, one, two, or three hours before the predetermined time. For example, if low temperatures (e.g., -3°C) and / or precipitation are predicted at the predetermined time and / or during the time preceding the predetermined time, the start time can be set earlier than if higher temperatures and / or no precipitation are predicted, thereby allowing more time for the screed to heat up.

[0055] Alternatively, or in addition, the start time can be determined based on the cooling parameters of the screed, for example, based on the method described in Figure 3.

[0056] After the start time is obtained, it can be provided that no further automatic actions are performed until the start time is reached. When the start time is reached in step 203, it can be checked whether the protective element described with reference to Figure 1 is correctly positioned (step 204). This is entirely optional and is preferably provided only if the corresponding protective element 130 is also provided.

[0057] If the protective element is not properly positioned, the control unit will not activate the screed heating as already described with reference to Figure 1. This means there will be no heating 206. Instead, in step 207, corresponding information may be optionally transmitted, for example, to an application on the operator's mobile device or to the screen of the operating element 182, thereby informing the operator that the screed heating has not been initiated.

[0058] For example, based on this information which can be transmitted as light or sound communication to the operator, the operator may then be instructed, for example, to correctly position the protective element. Alternatively, or in addition, an option may be presented to the operator to authorize the start of heating of the road finishing machine even if the protective element is not correctly positioned. If the operator confirms this, heating may be activated by the control unit despite the protective element not being correctly positioned.

[0059] If the protective elements are correctly positioned, or if this is not verified in step 204, the screed is subsequently heated automatically by supplying energy to the heating means, for example, from the road finishing machine's accumulator 141, as already described with reference to Figure 1.

[0060] Figure 3 shows a further method 300 that can be performed alternatively to or in combination with steps 202 and 221.

[0061] This method begins in step 301, where a predetermined time is obtained for the screed to be heated to a desired operating temperature.

[0062] Next, the screed is heated to a test temperature. This test temperature is preferably lower than the operating temperature of the screed and may include heating starting from the current temperature of the screed by a specific Kelvin number independent of the operating temperature of the screed. For example, the screed may be heated by 10K, 20K, or 30K. Other values ​​are possible, as long as a reliable determination of the parameters associated with the cooling of the screed, which will be described hereafter in step 304, is possible. Alternatively, the screed may be provided to be heated to the same test temperature at all times, similarly independent of the current temperature of the screed and / or the ambient temperature. This test temperature may be, for example, 60°C.

[0063] After the screed is heated to the test temperature in step 302, the screed heating means is turned off, and the screed is cooled in step 303. This cooling ultimately cools the screed to ambient temperature without the heating means being turned on again.

[0064] The cooling of the screed to ambient temperature, particularly the time history of this cooling process, depends on the physical parameters of the screed. Specifically, the amount of heat present in the screed at the test temperature T corresponds to Q = α × T, where T is the absolute temperature and α generally represents the heat capacity (J / K) of the screed. In the simplest case, where the screed consists of exactly one material representing the total mass of the screed, α = c × m, where c is the specific heat capacity and m is the mass of the screed.

[0065] However, since the screed consists of different components and, in particular, different materials, the heat capacity α is generally more complex, especially the specific heat capacity and the sum of the products of the masses of the individual components of the screed. However, within the scope of the present invention, it has been found that, with respect to the heating of the screed, it is not necessary to determine the contribution of each component of the screed to the heat capacity, and in short, only the heat capacity of the screed needs to be determined.

[0066] The temperature progression of the screed during cooling is e ?k(?)t Since it depends on time T(t) which is proportional to T0, T(t) = (T0 - T u )e -k(α)t +T u (T0 is the test temperature, T u (where is the ambient temperature), and from the cooling behavior, particularly the temperature progression over time, the physical properties of the screed can be derived at least numerically. The parameter k(α) associated with cooling can be determined in this way. This is done after the temperature progression of the screed is measured, for example, by an internal temperature sensor which can be connected to a control unit, in step 304. In step 304, from this measurement, the parameter k(α) can be determined as a parameter of the screed associated with the cooling behavior (also referred to as a cooling parameter), or the heat capacity α of the screed can be obtained from the parameter k(α). This can be done by additionally determining the amount of heat released from the screed during the cooling process.

[0067] Therefore, the behavior of the screed during cooling, particularly its temperature, can be measured at different points in time after the heating means is turned off in order to numerically evaluate the exponential progress described above. For example, the temperature of the screed can be measured every 30 seconds over a 20-minute period after the heating means is turned off at the end of step 302.

[0068] Thus, in relation to the cooling of the squeegee, the parameter k(α) or α determined in step 304 can subsequently be used in step 305 (e.g., in combination with further information such as the ambient temperature and the operating temperature of the squeegee to be achieved) to determine the start time based on the time predetermined in step 301. The determination of the start time can basically include the output of the heating means in all the described embodiments, because the output determines the amount of heat per unit time that can be supplied to the squeegee.

[0069] This can advantageously be used to select the start time, so that, for a given ambient temperature and the operating temperature of the squeegee to be achieved, there is preferably a start time of exactly the length up to a predetermined time, which is achieved in the time interval in which the heating of the squeegee to the operating temperature, preferably reaching the predetermined time as a result, occurs. Also thereby, an "idle time" is avoided in which the squeegee is heated to the required operating temperature but has not yet reached the predetermined time, which is advantageous from the perspectives of environmental protection and economy.

[0070] Based on the heating to the test temperature and the subsequent cooling in steps 302 and 303, it can also be provided that, instead of determining the parameter associated with cooling, the parameter associated with heating is determined in the manner corresponding to FIG. 3. This can then also be used to obtain the start time in step 305.

[0071] In this embodiment, for example, the measurement of the temperature of the squeegee is performed during the heating to the test temperature in step 302. This can be measured, for example, every 30 seconds over the period during which the squeegee is heated from the ambient temperature T u to the test temperature T0, corresponding to the above description. In this case, the parameter k(α) associated with the heating of the squeegee is then T(t)=(T u -T0)e -k(α)t +T0 (T0 is the test temperature, T uThe relationship between the ambient temperature and the parameters associated with the heating of the screed can also be understood as heating parameters.

[0072] After reaching the test temperature, in this embodiment as well, the heating means can be turned off, and the screed can be cooled again accordingly. Corresponding to the embodiment in Figure 3, it may also be provided that in step 304, the cooling parameters are determined. It may further be provided that both the cooling parameters and the heating parameters are used in step 305 to obtain the start time. For example, the average value from the determined cooling parameters and the determined heating parameters can be used to obtain the start time 305.

Claims

1. A method (200) of heating a screed (110) of a road finisher (100), comprising: Obtaining a predetermined time for operating the screed (201); obtaining a start time for starting heating of the screed based on the predetermined time (202); Automatically heating (205) the screed (110) from said starting time by supplying energy from an energy source (141) to heating means (112) of said screed; A method comprising:

2. 2. The method of claim 1, wherein the energy source is or comprises an accumulator connected to a main drive (140) of the road finisher (100), or a fuel cell connected to the main drive (140) of the road finisher (100), or an external energy source connected to the main drive (140) of the road finisher (100), or the road finisher (100).

3. 3. The method of claim 1 or 2, wherein deriving (202) the start time is further performed based on measured environmental parameters (221).

4. The method of claim 3 , wherein the environmental parameters include at least one of ambient temperature, humidity, precipitation per unit time, and brightness.

5. The method of claim 1, wherein obtaining (305) the start time is further performed based on measured cooling and / or heating parameters of the screed (110).

6. 6. The method of claim 5, wherein the measured cooling parameters are determined by heating (302) the screed (110) to a predetermined test temperature and subsequently determining (304) a parameter associated with the cooling of the screed, and / or the measured heating parameters are determined by heating (302) the screed (110) to a predetermined test temperature and subsequently determining a parameter associated with the heating of the screed.

7. 2. The method of claim 1, wherein the automatic (205) heating of the screed (110) is activated by a control unit (180) only when the control unit (180) receives a signal indicating the positioning of a protective element (130).

8. The method of claim 7, wherein the protective element (130) comprises a non-combustible material and / or a thermal insulating material.

9. 2. The method of claim 1, wherein obtaining (202) the predetermined time is achieved based on inputs in operating elements (182) of the road finisher (100) and / or based on inputs of input means connected to a control unit (180) of the screed by wireless connection.

10. A road finishing machine (100) comprising a screed (110) and a control unit (180), said screed and said control unit being configured to perform a method for heating said screed, said method comprising: Obtaining a predetermined time for operating the screed (201); obtaining a start time for starting heating of the screed based on the predetermined time (202); automatically heating the screed from said starting time by supplying energy from an energy source to heating means of said screed (205); Including, road finishing machines.

11. 11. The road finishing machine of claim 10, wherein the energy source is or comprises an accumulator connected to a main drive (140) of the road finishing machine (100), or a fuel cell connected to the main drive (140) of the road finishing machine (100), or an external energy source connected to the main drive (140) of the road finishing machine (100), or to the road finishing machine (100).

12. 12. A road finishing machine (100) according to claim 10 or 11, comprising a sensor (190) for measuring an environmental parameter, and wherein the control unit (180) is embodied to determine the start time based on the measured environmental parameter.

13. 11. A road finisher (100) according to claim 10, wherein the control unit (180) is configured to determine the start time based on cooling parameters of the screed (110) stored in a memory (181) of the control unit.

14. 11. A road finisher (100) according to claim 10, wherein the control unit (180) is configured to activate the heating of the screed (110) only when the control unit receives a signal indicating the positioning of a protective element (130).

15. 15. The road finisher (100) of claim 14, wherein the protective element (130) comprises a non-combustible material and / or a thermal insulating material.

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