Clamping device for providing tree trunks with intact bark and the bark obtained from them for the production of shingles and panels.

Abstract

Clamping device (10) for clamping and gripping a tree trunk with saw surfaces of a defined length - two movable pliers (20, 30), and - one bar (40), - wherein the two clamps (20, 30) are movably connected to the rod (40) at opposite ends, - wherein each pair of pliers (20, 30) consists of two arc-shaped, preferably crescent-shaped, flat arms which are connected at a distance from each other, - wherein each arm of a pair of pliers has a first end (21, 31) and a second end (22, 32), - wherein the first end (21, 31) of each arm has a pointed shape for engaging / gripping the tree trunk at the saw surfaces, - wherein the second end (32, 32) of each arm has a fastening means for movably attaching the pliers to the rod, and - wherein each of the two clamps (20, 30) is provided with a means for receiving at least one rope strap (24, 25), wherein the rope straps are designed for swiveling suspension on a crane.

Description

[0001] The present invention relates to a clamp device for providing tree trunks with intact tree bark and without mechanical destruction of the tree bark, so that the tree bark is suitable for the production of large-format boards and panels.

[0002] The present invention also relates to the tree bark obtained for the production of shingles and panels and for use as flame-retardant boards. Description

[0003] When processing trees into boards and beams, knots, tree bark, and sawdust are generated as residual materials. Currently, knots and leftover wood strips are primarily machined and processed into particleboard with sawdust and binding agents. Tree bark is composted as waste material because its strength is considered insufficient even for simple particleboard.

[0004] In contrast to the widespread use of tree bark as waste and fuel today, tree bark was once partly used for facade cladding. For example, contract peelers, lumberjacks, and dairymen were the first in Austria to apply large areas of tree bark to foresters' lodges and lumberjack huts as exterior cladding. Previously, such bark was manually peeled from felled trees by forest workers.

[0005] The use of tree bark for surface cladding was taken up again in DE 10 2015 010 007 A1. Here, the tree bark is peeled while still naturally moist and subjected to pressure of 1-9 tonnes / m 2 Formed flat and dried under heat at 80-200°C. After cutting the formed and dried tree bark, it is partially glued to a substrate (such as wood, metal, plastic, or mineral).

[0006] The process of DE 10 2015 010 007 A1 therefore requires high pressures and temperatures, which does not have a negative impact on the properties of the tree bark (such as long-term stability) but is not suitable for all tree species. These process conditions also require a high level of equipment expenditure.

[0007] In addition to processing tree bark, harvesting the bark presents a challenge. The goal is to peel as large pieces of bark as possible from the felled trees without damaging the bark.

[0008] Previously available mechanical methods such as the use of traditional harvesters, as described in AT271858 or AT236627, are not suitable for this task, as they cause excessive damage to the outside of the tree trunks and thus to the bark.

[0009] It was therefore an object of the present invention to provide a device which enables the tree bark to be transported in a manner which is as non-destructive as possible, so that large pieces of bark can be peeled for the production of large-format boards and panels.

[0010] This object is achieved by a device having the features of claim 1.

[0011] Accordingly, a pliers device for clamping and gripping a tree trunk having sawn surfaces and a defined length is provided, the device comprising: - two pliers, and - a rod connecting the two clamps, - wherein the two clamps are each movably connected to the rod at the opposite ends of the rod, - each pair of pliers consists of two curved, preferably sickle-shaped, flat arms which are connected to each other at a distance, - each arm of a pair of pliers having a first end and a second end, - the first end of each arm has a (pointed) shape for engaging / gripping the tree trunk at the sawing surfaces, - wherein the second end of each arm has a fastening means for movably attaching the pliers to the rod, and - wherein a means for receiving at least one rope belt is provided on each of the two tongs, wherein the rope belts are designed for pivotable suspension on a crane.

[0012] In one embodiment, the two pliers are each movably connected to the rod at the opposite ends of the rod by means of a fastening means, preferably by means of a hinge or joint.

[0013] Furthermore, the distance between the two clamps along the pole can be flexibly adjusted depending on the length of the tree trunk. For this purpose, the pole can have multiple fastening elements for a hinge or joint (arranged along the pole), or the pole can be designed in the shape of a telescope.

[0014] Both pliers and the rod are made of suitable alloy metals.

[0015] With this device, it is now possible to grip or lift tree trunks (or logs) of a specific length (4.00-4.20 m) after felling and cutting them to size, avoiding damage to the tree bark. To do this, the tree trunks are gripped at the sawing surfaces with two tongs, rather than being lifted with a tong that grips the tree trunk as is usually the case.

[0016] As described, the present device for gripping the log or tree trunk comprises two movable clamps (each consisting of two sickle-shaped arms). These two clamps can be pivoted between a minimum and a maximum distance, with the maximum distance approximately corresponding to the length of the log to be gripped.

[0017] The movable tongs are each mounted on opposite ends of a rod via a suitable hinge. The rod serves to stabilize the device. The rod with the two movable tongs is placed or positioned along the log to be transported, with the pointed ends of the tongs gripping the circular sawing surfaces of the log on both sides.

[0018] Each tong is attached to a rope strap, the ends of which are connected to a crane hook. Lifting the crane tensions the rope straps, transferring the tensioning force to the tongs and firmly clamping the log between them.

[0019] The clamped block can be moved and transported, e.g. loading or unloading onto or from transport vehicles, without causing any destruction of the bark.

[0020] With this device, the felled trees (logs) can be transported as quickly and as damage-free as possible from the forest to the peeling site, where further processing and stacking take place.

[0021] Further processing of the logs includes peeling the tree bark, which is typically done manually using peeling irons.

[0022] The peeled tree bark is then usually preserved using a gentle process involving pressure and heat.

[0023] However, the relatively high flammability of tree bark prevents a wider use of tree bark, especially for indoor use.

[0024] It was therefore a further object of the present invention to provide a tree bark that is as flame-resistant as possible, and in particular to make tree bark from tree barks of various tree species that were previously classified as waste material usable for use as design panels in interior design or as facade cladding.

[0025] The treatment of tree bark should also be carried out using the most gentle and ecological process possible.

[0026] This object is achieved with a tree bark comprising the features of claim 4.

[0027] Accordingly, a flame-resistant tree bark for the production of shingles and panels is provided, wherein the flame-resistant tree bark is obtainable in a process comprising the following steps: - Providing tree bark with a moisture content of up to 60% by peeling the tree bark including the bast layer from selected trees; - drying the tree bark in wood dryers with cross ventilation at temperatures between 50 and 70°C, preferably between 60 and 65°C for a period of 2 to 10 days, preferably 4 to 8 days, under ambient pressure, in particular at 0.1 MPa (1 bar), and - Treating the tree bark after drying with a flame retardant, particularly in a printing or non-printing process.

[0028] This makes it possible to provide flame-resistant or flame-protected tree bark, whereby the peeled tree bark is subjected to gentle treatment.

[0029] The tree barks are preferably separated from the various trees in large areas and then preserved using the most gentle method possible, applying pressure and heat.

[0030] Large-scale bark stripping requires a moisture content of between 30 and 60%, preferably between 40 and 60%. If the moisture content of the tree bark is below these values, large-scale bark stripping is no longer possible; instead, the tree bark will crack. Ideally, bark stripping should take place in early summer, i.e., at a time when the tree bark is at its most moist due to its growth stage.

[0031] The bark of different tree species requires different finishing processes due to their properties. Poplar bark is the most ecologically valuable product, as it requires only minimal further treatment, while other barks are applied to carrier boards with binding agents for stabilization. All barks can be preserved using this process. In the final step, the bark is sawn into customer-specific formats.

[0032] Tree bark drying is preferably carried out in wood dryers with cross ventilation, which also allow for the drying of larger quantities of bark. Moisture meters are attached to the bark, which transmit their data to a control system. Based on this data, drying programs tailored specifically to the individual bark types are applied. The vapor-tight and thermally insulated wood dryers utilize a proven fresh air and exhaust air principle, in which fans circulate warm air, allowing the interior climate to be precisely controlled.

[0033] In the process described here, the barks are slowly heated for several days, preferably for 2-4 days, to a temperature of only 50-70°C, preferably 60° - 65°C, following a controlled drying process.

[0034] This gentler drying process, which is specifically tailored to the different bark types, leaves the bark surfaces intact and retains their original appearance. At the same time, it also achieves disinfestation of the bark, i.e., the destruction of animal pests. Thermal pest control is generally carried out without the use of poisons and is therefore an environmentally friendly alternative to the conventional use of insecticides. Protein coagulation, or denaturation, begins in pests at temperatures above 42 degrees Celsius. This results in a change in the biomolecules and a loss of the cell's ability to produce proteins. Once the bark has reached a sufficient moisture content for further processing, it is completely disinfested and gently preserved for later use. Subsequent surface coating with chemicals or varnishes is therefore no longer necessary.

[0035] The drying process allows for (pre-)drying of the bark panels to an equilibrium moisture content of 16-18% to ensure optimal conditions for subsequent treatments.

[0036] The pre-dried bark can then undergo a further step of carbonization (charring). During carbonization, the cellulose in the wood is partially cross-linked and partially charred. This changes various material properties such as color, odor, hardness, and biodegradability. Applying the carbonization process can alter the structure of the bark and increase its fire resistance.

[0037] In one embodiment of larch, the flame-resistant tree bark is glued to a suitable carrier board.

[0038] Suitable carrier boards can be wood-based panels, in particular a veneer plywood board (e.g. a multiplex board) or other plywood boards.

[0039] Wood glues or polyurethane glues can be used to bond the tree bark to the carrier board. Typical glues are waterproof D3 or D4 wood glues or PUR glues.

[0040] The drying process can be applied to tree bark that has already been applied to the substrate or carrier board prior to drying. In this variant, the tree bark is applied to at least one carrier board in a moist state, particularly with a moisture content of up to 20% after outdoor storage, before drying and glued to the at least one carrier board.

[0041] In another version, the peeled tree bark is dried without a backing board. Instead, some tree bark is applied to at least one backing board after drying, and then glued and, if necessary, pressed to the backing board.

[0042] In yet another variant, it is possible to use the dried tree bark without gluing it to a carrier board, i.e., the dried tree bark is used as is. Heated presses can be used to stabilize the bark (without a carrier board).

[0043] This makes it possible to provide tree bark for a variety of applications. Depending on the tree species, the bark can be attached to a support material in a dry or wet state, or it can be used without a support material.

[0044] In addition to their aesthetic value, the tree barks also possess sound-absorbing properties and, after special finishing, can also be classified as fire protection class B1 according to EN 13501-1, which further expands their application possibilities. To meet fire protection requirements, the tree bark is finished after drying using two different processes: the printing process and the non-printing process.

[0045] Salts from the group comprising phosphates, borates, especially ammonium polyphosphate, tris(tribromoneopentyl)phosphate, zinc borate, or boric acid complexes of polyhydric alcohols, magnesium hydroxide, or aluminum hydroxide are preferred as flame retardants. Boron-free fire retardants based on phosphorus compounds are preferred.

[0046] In the pressure process, these salts are absorbed by the bark in special impregnation tanks by applying pressure. In this vacuum pressure process, the bark is first deaerated at a pressure of 0.10 - 0.35 bar, depending on the bark type, for between 30 and 45 minutes. The maximum wood moisture content must not exceed 30%.

[0047] The impregnation cylinder is then flooded with a liquid in which the special salts have been dissolved, while maintaining a vacuum. A pressure of 8-9 bar then ensures that the bark is impregnated for between 45 and 500 minutes, preferably 60 to 300 minutes, depending on the wood species and dimensions. Once sufficient liquid and thus dissolved salts have been absorbed by the bark, a final vacuum at 0.5 bar is applied for up to 20 minutes, preferably 5 to 15 minutes, to prevent the impregnation liquid from dripping. Since the impregnation liquid is water with harmless salts, preventing the release of the impregnation liquid or the aerosols generated during the process can be neglected.

[0048] Of the various non-printing processes, storage processes are used. Depending on the wood species, the bark is treated either by immersion impregnation or trough impregnation. In immersion impregnation, the bark is immersed in a liquid containing the flame-retardant salts for a period of one to several hours, preferably 1 to 24 hours. With trough impregnation, this can take from one to several days, preferably 1 to 3 days. In principle, both non-printing processes are technically identical.

[0049] The systems consist of a drinking trough or dipping basin filled with the salts dissolved in a liquid, a wooden support with a lifting mechanism, and a holding device that presses the bark into the liquid. Level monitoring with an overflow protection device for the drinking trough and automatic shutdown of the lifting device ensures that the liquid does not overflow. When extended, the bark must remain above the drinking trough until no more liquid drips off. This can be accelerated by tilting the bark.

[0050] The choice of process depends on the intended use of the B1-certified bark. In general, the salts penetrate less deeply into the bark with the non-pressure process than with the pressure process.

[0051] The amount of salt absorbed by the bark can be determined using various methods. One possibility, for example, is to first determine the weight of the dry bark before impregnation. After impregnation, the weight of the bark saturated with the saline liquid is determined. After drying, the bark is weighed again. The resulting weight difference can be used to determine the salt content in the bark.

[0052] After impregnation with the flame retardant, the treated bark panels are (re)dried to an equilibrium moisture content of 16-18%.

[0053] In a further embodiment, after drying the tree bark, no further coating of the dried tree bark with varnishes, resins, or oils takes place; ie, the flame-resistant tree bark has no further coating on its surface.

[0054] The present tree bark is preferably selected from a group of tree species including poplar, larch, birch, alder, spruce, oak, Douglas fir, and others. The use of poplar bark is particularly preferred.

[0055] After drying and, if necessary, gluing, the tree bark is cut into suitable formats in a further process step.

[0056] The integrity of large areas and the resulting individuality of the individual barks, as well as the preservation of these without the use of varnish or similar chemicals, which are maintained by the particularly ecological process using pressure and heat, represent the inventive features of the present processing method.

[0057] This flame-resistant tree bark can be used for interior construction, particularly in the form of large-format panels, or for furniture construction, but also for exterior construction, particularly as facade cladding.

[0058] In one application, the treated tree bark is used in the form of shingles or large panels for the interior design of commercial, public, and private spaces. They can be used over large areas or as a design highlight, like a picture. They can be used temporarily in trade fair construction, but also as a natural alternative to conventional wall cladding. Poplar bark, thanks to its completely natural production, can even be used in the interior design of saunas.

[0059] The shingles can also be used to enhance the surface of furniture, for example, on bedside tables, cabinets, bar counters, etc., as well as for wall cladding. The bark can also be used in a variety of artisanal products.

[0060] Many barks can also be used as facade cladding. The finished bark panels are mounted on rails and hung directly onto the facade walls using a process specially developed for facade construction.

[0061] The present invention will be explained in more detail below using exemplary embodiments with reference to the figures. They show: Fig. 1 an embodiment of the pliers device according to the invention. Example 1:

[0062] First, the tree bark is stripped, including the bast layer, which can only be done at certain times of the year. The largest possible areas of still-moist bark are stacked and weighted down. Fresh from the forest, the bark's moisture content is approximately 60%. This value drops quite quickly to below 20% when stored outdoors.

[0063] Some tree barks allow bonding even in this moist state using a special polyurethane (PU) D4 glue. The PU glue is a gap-filling, heat-resistant, solvent-free reactive adhesive and allows bonding of the barks to the carrier boards at a wood moisture content of up to 19%. This shortens laborious, time-consuming pre-drying and repeated restacking, allowing for prompt application of the barks.

[0064] All barks, even those that are not wet glued and those that do not require a carrier material, are subjected to a special, more environmentally friendly, energy-saving drying process.

[0065] This takes place in wood dryers with cross ventilation, which also allow for the drying of larger quantities of bark. Moisture meters are attached to the bark, which transmit their data to a control system. Based on this data, drying programs tailored specifically to the individual bark types are applied. The vapor-tight and thermally insulated wood dryers utilize a proven fresh air and exhaust air principle, in which fans circulate warm air, allowing the interior climate to be precisely controlled. In the process described here, the bark is slowly heated to a temperature of only 60°-65°C for several days.

[0066] This gentler drying process, specifically tailored to the different bark types, leaves the bark surfaces intact and retains their original appearance. At the same time, it also achieves disinfestation of the bark, i.e., the destruction of animal pests. Thermal pest control is generally carried out without the use of poisons and is therefore an environmentally friendly alternative to the conventional use of insecticides. Protein coagulation, or denaturation, begins in pests at temperatures above 42 degrees Celsius. This results in a change in the biomolecules and a loss of the cell's ability to produce proteins. Once the bark has reached a sufficient moisture content for further processing, it is completely disinfested and gently preserved for later use.A subsequent surface coating with chemicals or varnishes is therefore no longer necessary, but can be applied later depending on the application.

[0067] Barks that are not glued in the wet state but require a carrier board are glued to the carrier board after disinfestation.

[0068] However, the de-insectized bark can also be used without a carrier plate.

[0069] The tree bark is used in the form of shingles or large panels for indoor or outdoor use. Example 2: Fire protection treatment

[0070] Peeling the tree bark is carried out analogously to Example 1.

[0071] The peeled tree bark is pre-dried to an equilibrium moisture content of 16-18% to ensure optimal conditions for subsequent treatments. This is done in a wood dryer with cross ventilation, similar to Example 1.

[0072] This is followed by a carbonization step (charring) of the dried tree bark in order to change the structure of the bark and increase its fire resistance.

[0073] In the following impregnation step, a boron-free, phosphorus-based fire retardant is used. It is important to check beforehand whether this fire retardant is compatible with the selected bark type.

[0074] The impregnation step is carried out using a tank-vacuum process. For this, the bark panels are first placed in the impregnation tank, and a vacuum is applied to remove air from the pores of the bark. The fire retardant is poured into the tank, and the pressure in the tank is increased to force the impregnation solution deep into the bark. Sufficient exposure time is ensured so that the fire retardant can fully penetrate the bark.

[0075] The impregnation is followed by a drying and stabilization phase in which the treated bark panels are re-dried to an equilibrium moisture content of 16-18%.

[0076] Storage of the fire-retardant-treated bark panels requires controlled conditions to ensure even moisture distribution and material stability. Embodiment 3: Pliers device according to the invention

[0077] A maximum of three sections (logs) can be cut from a whole tree. Each log is approximately 4.10 m long and weighs up to 2 tons.

[0078] After felling, a log is picked up in the forest using the inventive clamp device, loaded onto a trailer, transported to the barking site, and unloaded from the trailer. The bark is then removed manually.

[0079] As in Fig. 1, the pliers device according to the invention has two movable pliers (20, 30) and a rod (40) provided between the pliers for stabilization.

[0080] The two clamps (20, 30) are each movably connected to the rod at the opposite ends of the rod (40).

[0081] Each pair of pliers (20, 30) consists of two curved, preferably sickle-shaped, flat arms. Both arms are connected to each other at a defined distance, e.g., via webs.

[0082] Each arm of a pair of pliers has a first end (21, 31) and a second end (22, 32), wherein the first end (21, 31) of each arm has a preferably pointed shape for engaging / gripping the tree trunk at the sawing surfaces, and wherein the second end (32, 32) of each arm has a fastening means for movably attaching the pliers to the rod.

[0083] The two clamps (20, 30) can be pivoted between a minimum distance (approx. 3.2 m) and a maximum distance (approx. 4.2 m), the maximum distance corresponding approximately to the length of the block to be grasped.

[0084] The rod with the two movable tongs is placed or positioned along the log to be transported, with the first (pointed) ends of the tongs gripping the circular sawing surfaces of the log on both sides.

[0085] Furthermore, a means for receiving at least one rope belt (24, 25) is provided on each of the two tongs (20, 30), wherein the rope belts are designed for pivotable suspension on a crane.

[0086] The rope belts (24, 25) are suspended from a hook of a crane. By lifting the crane, the rope belts are tensioned, whereby the tensioning force is transferred to the tongs and a firm clamping of the block between the tongs is effected.

[0087] The clamped block can be moved and transported, e.g. loading or unloading onto or from transport vehicles, without causing any destruction of the bark. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2015 010 007 A1 [0005, 0006] AT 271858

[0008] AT 236627

[0008]

Claims

[1] Pliers device (10) for clamping and gripping a tree trunk having sawn surfaces and a defined length, comprising - two movable clamps (20, 30), and - a rod (40), - wherein the two clamps (20, 30) are each movably connected to the rod (40) at the opposite ends of the rod, - wherein each pair of pliers (20, 30) consists of two curved, preferably sickle-shaped, flat arms which are connected to one another at a distance from one another, - wherein each arm of a pair of pliers has a first end (21, 31) and a second end (22, 32), - wherein the first end (21, 31) of each arm has a pointed shape for engaging / gripping the tree trunk at the sawing surfaces, - wherein the second end (32, 32) of each arm has a fastening means for movably attaching the pliers to the rod, and - wherein on each of the two tongs (20, 30) a means is provided for receiving at least one rope belt (24, 25), wherein the rope belts are designed for pivotable suspension on a crane. [2] Pliers device according to claim 1, characterized by that the two pliers (20, 30) are each movably connected to the rod (40) at the opposite ends by means of a fastening means, preferably by means of a hinge or joint. [3] Pliers device according to claim 1 or 2, characterized by that the distance between the two clamps (20, 30) along the rod (40) can be flexibly adjusted depending on the length of the tree trunk. [4] Flame-resistant tree bark for the manufacture of shingles and panels obtainable in a process comprising the following steps: - Providing tree bark with a moisture content of up to 60% by peeling the tree bark including the bast layer from selected trees; - drying the tree bark in wood dryers with cross ventilation at temperatures between 50 and 70°C, preferably between 60 and 65°C for a period of 2 to 10 days, preferably 4 to 8 days, under ambient pressure, in particular at 0.1 MPa (1 bar), and - Treating the tree bark after drying with a flame retardant in a printing or non-printing process. [5] Tree bark according to claim 4, characterized by that the tree bark is glued to a carrier board. [6] Tree bark according to claim 5, characterized by that the at least one carrier plate is a wood-based panel, in particular a veneer plywood panel (e.g. a multiplex panel) or other plywood panel. [7] Tree bark according to claim 4, characterized bythat the tree bark is used after drying without gluing to a carrier board. [8] Tree bark according to any one of claims 4-7, characterized by , which uses as flame retardant salts from the group comprising phosphates, borates, in particular ammonium polyphosphate, tris(tri-bromoneopentyl)phosphate, zinc borate or boric acid complexes of polyhydric alcohols, magnesium hydroxide or aluminum hydroxide. [9] Tree bark according to any one of claims 4-8, characterized by that the tree bark meets the requirements of the fire protection class according to EN 13501-1. [10] Tree bark according to any one of claims 4-9, characterized by that after drying the tree bark, no further coating of the dried tree bark with varnishes, resins or oils takes place. [11] Tree bark according to any one of claims 4-10, characterized bythat the tree bark of tree species is selected from a group including poplar, larch, birch, alder, spruce, oak, Douglas fir and others. [12] Tree bark according to any one of claims 4-11, characterized by that the dried and, if necessary, glued tree bark is cut into suitable formats.

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