STRUCTURE OF A MACHINE TOOL

Description

Scope of the invention

[0001] The present invention relates to a machine tool structure according to the preamble of claim 1. Such a machine tool structure is known from document WO 2017 / 158059 A1. State of the art

[0002] In the field of machining, particularly woodworking, there are machine tools designed to shape tree trunks into pieces of wood of predefined dimensions for use in building construction.

[0003] In particular, we know of planers adapted to transform pieces of wood, typically tree logs, in order to first straighten the pieces of wood, then to machine them in order to produce beams or planks for example intended to constitute structural parts of buildings.

[0004] Machining is performed by rotating cutting tools and the piece of wood is moved in translation from an input to an output of the machine tool.

[0005] Timber planers for framing typically consist of a fixed lower frame containing a worktable. The frame includes lifting columns, for example, jacks, connecting it to an upper frame, forming a gantry. The gantry supports a cutting tool for planing the upper portion of a workpiece placed on the worktable.

[0006] The lifting columns allow the height of the cutting tool carried by the gantry to be changed, that is to say the distance between said cutting tool and the machining table so as to vary one of the dimensions, here called the thickness, of the structural pieces produced.

[0007] For this purpose, the lifting columns are generally distributed around the machining table and include a cylinder forming a sleeve fitted in the frame and in which a cylinder rod mechanically linked to the upper part is adapted to slide.

[0008] However, the lifting columns of state-of-the-art machine tools do not allow for large travel strokes.

[0009] Furthermore, state-of-the-art machine tools do not offer the possibility of modifying their maximum stroke, for example in the case where large pieces of wood need to be machined.

[0010] In this case, only a substantial and costly modification of the machine tool is feasible, or a complete change of the machine tool must be considered.

[0011] The disadvantages of a machine tool adapted for machining wood have been described previously, but it should be noted that these disadvantages are also found on state-of-the-art machine tools adapted for machining other types of materials. Description of the invention

[0012] The present invention aims to remedy all or part of the drawbacks of the prior art, in particular those set out above.

[0013] To this end, the present invention proposes a machine tool structure, particularly intended for machining wooden parts, comprising a frame including: a support base, a machining table resting on said base and on which the pieces of wood to be machined are intended to be driven, an upper frame, support columns interposed between the support base and the upper frame.

[0014] The machine tool structure further includes a tool apron connected to translational drive elements, interposed between the upper frame and the support base, and configured to drive the tool apron by sliding between the machining table and the upper frame.

[0015] In particular embodiments, the invention may further comprise one or more of the following features, taken individually or in all technically possible combinations.

[0016] In one embodiment, the tool-carrying apron includes at least one carriage rigidly attached to it. In another embodiment, the carriage is rigidly attached to a cylindrical sleeve. In yet another embodiment, the carriage includes an element cooperating with a drive element that allows the carriage to move along an axis, preferably a vertical axis. The drive element may be, for example, a rack and pinion system, a pneumatic cylinder, a drive roller, or any other drive element. The drive element preferably includes a motor element, such as an electric motor, a geared motor, or any other drive element.

[0017] In particular embodiments, the translational drive elements are formed by electric cylinders, each comprising a worm screw fixed at each of its ends respectively to the upper frame and the support base, in a movable rotational manner, said electric cylinders further comprising each a carriage cooperating with the worm screw by a helical link, said carriages being fixed to the tool-carrying apron.

[0018] In particular embodiments, the worm gears are driven in rotation by angle gearboxes arranged on the upper frame and connected to each other by drive shafts linked to an output shaft of an electric motor.

[0019] In particular embodiments, the machine tool structure includes stabilizing means formed by cylindrical sleeves fitted around the support columns in a free translational manner, said sleeves being rigidly fixed to the carriages.

[0020] The cylindrical sleeves are fixed to the large tool holder, which has a diameter of 160 to 200 millimeters. The cutting length is approximately 1300 millimeters. Such a tool holder allows machining the upper part of large glulam beams that can reach 1000 millimeters in thickness, 1200 millimeters in width, and 11,000 to 50,000 millimeters in length. The tool holder is preferably made of steel. The angular speed of the tool holder is preferably between 6,000 and 8,000 revolutions per minute. The tool holder is preferably driven by a motor mounted on the tool holder.

[0021] In particular embodiments, the stabilizing means comprise flanges, each flange being fixed to one end of a sleeve and having a through opening through which a support column extends.

[0022] In particular embodiments, each trolley is interposed between and is mechanically connected to two adjacent sleeves, a support column being arranged at each of the corners of the upper frame. Presentation of the figures

[0023] The invention will be better understood upon reading the following description, given by way of non-limiting example, and made with reference to the figures which represent: [ Fig. 1 ] a front view of a machine tool structure according to the present invention, [ Fig. 2 a side view of the machine tool structure of the figure 1 , [ Fig. 3 a detailed view of the figure 2 , [ Fig. 4 A detailed view of the linkage between the linear drive elements and a tool holder apron of the machine tool structure of the figure 1 , [ Fig. 5 a three-quarter view of one side of the machine tool structure of the figure 1 , [ Fig. 6a three-quarter view of one side of the machine tool structure of the figure 1 .

[0024] In these figures, identical references from one figure to another designate identical or analogous elements. For clarity, the elements shown are not necessarily to the same scale, unless otherwise stated.

[0025] It should be noted from the outset that the figures are not to scale. Detailed description of an embodiment of the invention

[0026] The present invention relates to a machine tool structure 10, in particular intended, in one example of application, for machining wood, for example solid or glued laminated wood, and in particular for planing the latter.

[0027] It should be noted that the present invention can also be applied, without structural modification, to a machine tool adapted for machining other types of materials.

[0028] The machine tool structure 10, as shown on the figure 1 , comprises a frame formed by a support base 11, a machining table 12 resting on said base, an upper frame 13 and support columns 14 interposed between said upper frame 13 and said base.

[0029] The machine tool structure 10 further includes a tool holder 15 designed to support, in the embodiment shown in the figures and described below, a planing tool. A planing tool allows the wood workpiece to be thickened to a chosen dimension.

[0030] The tool apron 15 is connected to translational drive elements 16 designed to move it in translation between the upper frame 13 and the machining table 12 and thus modify the cutting thickness of the planing tool.

[0031] The machining table 12 is intended to receive a piece of wood to be machined and may advantageously include means for guiding and driving the piece of wood to be machined.

[0032] It should be noted that the drive elements 16 and the support columns 14 are arranged on either side of the machining table 12, as shown in the figures 1, 2 , 5 and 6 , on the sides of the frame of the machine tool structure 10, said sides defining a corridor along which the piece of wood to be machined is intended to be driven in translation by suitable devices known in themselves to the man skilled in the art.

[0033] The machine tool structure 10 also supports woodworking tool holders, known as such to those skilled in the art. Such tool holders can be used to hold tools for planing or sawing workpieces moved along the machining table 12, in order to produce finished products such as beams, planks, etc.

[0034] The present invention relates to the structure of the machine tool 10; the arrangement of the tool holders will not be described below. Furthermore, this arrangement is within the grasp of a person skilled in the art.

[0035] Furthermore, in this application only the structure of machine tool 10 which is the subject of the invention will be described and not the machine tool as a whole.

[0036] As shown by figures 1, 2 , 5 and 6, the drive elements 16 are adapted to cause the movement of the tool-carrying apron 15 in a vertical direction, between the upper frame 13 and the machining table 12.

[0037] The machine tool structure is preferably designed for machining glued laminated timber beams. Before machining, these beams, made of glued and highly compressed wood lamellae, are produced in molds that allow for the desired dimensions and geometry to be imposed. Typically, the machine tool structure allows for the production of straight beams that are as rectilinear as possible. It should be noted that before machining, the as-formed beam has an excess of extremely hard and unevenly distributed glue on its exterior. Some areas of the beam also exhibit irregularities in the wood material. This results in potentially harsh cutting forces when the beam is machined by the tool holder 12.

[0038] These drive elements 16 can advantageously be formed by electric actuators, each comprising a worm gear 160 extending between the upper frame 13 and the support plate 11, said worm gears 160 being connected to said upper frame 13 and to said support plate by pivot joints. The worm gears 160 are driven in rotation by suitable means, such as right-angle drive devices 161 arranged on the upper frame 13 and connected to each other by drive shafts 162, themselves connected to an output shaft of an electric motor, for example by a right-angle drive device, as shown in the figures 1 to 3 .

[0039] This particular arrangement of the motion transmission elements, i.e. the transmission shafts 162 and the angle gearboxes 161, advantageously allows for possible replacements or modifications of the support columns 14 and the worm gears 160, as described below.

[0040] It should be noted that on the figures 1 to 4 The support columns 14 and the worm gears 160 appear surrounded by a protective sheath, and appear on the figures 5 and 6 without these protective sheaths.

[0041] Each cylinder also includes a carriage 163 cooperating with the worm gear 160 via a helical linkage. The carriages 163 are rigidly connected to the tool-carrying apron 15, as suggested by the figures 2 , 4 And 5 that is to say, linked by a mechanical connection of the fixed type.

[0042] The rotational drive of the worm screws 160 consequently causes the movement of the tool-carrying apron 15 in a direction opposite to the machining table or directed towards said table according to the direction of rotation of said screws.

[0043] As depicted on the figures 1 and 2 The machine tool structure 10 preferably includes stabilizing means formed by the support columns 14 rigidly fixed, as previously described, at each of their ends, respectively to the upper frame 13 and to the support base 11. These support columns 14 have in particular the role of maintaining said frame in a high position, away from the support base 11, and are therefore preferably arranged so that a support column 14 supports each of the corners of said frame.

[0044] The abrupt variations in cutting forces necessitate the use of stabilizing means to control shocks. These means are also driven vertically when it is necessary to adjust the height of the tool holder 15 to obtain the desired thickness of the machined beam. The invention thus allows for wide adjustments to the cutting height of the workpieces while maintaining sufficient overall rigidity to achieve the desired geometric quality during machining. Furthermore, adjusting the cutting height over a wide range is easy and does not require dismantling the machine tool structure 10 to significantly alter the desired cutting height. The machine tool structure 10 according to the invention therefore also offers significant time savings when the cutting height needs to be changed.

[0045] These stabilizers also provide resilience to the entire tool holder assembly, which a single massive machine tool gantry could not provide. If the tool holder were mounted on a solid cast iron or welded frame, the structure would be statically indeterminate.

[0046] The stabilizing means comprise cylindrical sleeves 140 fitted around each of the support columns 14, allowing free translation. The sleeves 140 are rigidly fixed to the carriages 163, as shown in the diagrams. figures 2 , 4 And 5 , and allow for translational guidance of the tool carrier apron 15 during its movement.

[0047] The structure according to the invention thus allows for the absorption, both within the structure itself and within the cylindrical sleeves, of the significant mechanical stresses induced by the wood cutting process. This design prevents excessive deformation of the structure, which could cause geometric displacement of the tool holder 15 and consequently compromise the geometric quality of the machined parts.

[0048] Machining the upper part of the beams makes it possible to obtain a constant thickness with a surface finish that meets the specifications.

[0049] This invention, due to the overall resilience, eliminates the vibrations that generate significant noise during machine operation.

[0050] In one embodiment, the tool holder 15 has tungsten carbide blades. This arrangement allows for flexible penetration of the glue and the wood material. Consequently, this arrangement eliminates the need to stop the machine during machining, as the tool holder 15 performs the function without damage.

[0051] In a preferred embodiment of the invention, the carriages 163 arranged on one side of the machine tool structure 10 are connected to each other by flanges with which they form a single piece, as can be seen in the figures 2 And 4 Each flange is rigidly fixed to one upper end of a sleeve 140 and has a through opening through which a support column 14 extends, as can be seen on the figures 1, 2 And 4 .

[0052] These characteristics make it possible to stiffen the machine tool structure 10 and to increase the resistance to mechanical stresses of the stabilizing means.

[0053] Advantageously, the sleeves 140 preferentially have an internal chamber opposite the support column 14 around which it is fitted, this internal chamber being designed to receive a grease to facilitate the sliding of said sleeves 140 along said support columns 14.

[0054] Preferably, each drive element 16 is interposed between two adjacent stabilizing means, i.e. each carriage 163 is mechanically connected to two adjacent sleeves 140, a stabilizing means being arranged at each of the corners of the upper frame 13, as described previously.

[0055] The stabilizing means and in particular the support columns 14 advantageously make it possible to stiffen the structure of the machine tool 10 and to absorb the mechanical forces and stresses generated during the operation of the machine tool, in particular during the operation of the planing tool.

[0056] According to one embodiment of the invention, the machine tool structure 10 comprises eight support columns 14. These support columns 14 are preferably located on the periphery of the machine. They are preferably located between the support base 11 and the upper frame 13. Preferably, each support column 14 is equipped with a stabilizing means.

[0057] In one embodiment, at least one support column 14 includes a foot connected to the support plate 11. In this embodiment, the foot is equipped with an elastic joint. The presence of an elastic joint between the foot of the support column 13 and the support plate 11 advantageously prevents indeterminacy. In another embodiment, each support column 13 has an elastic joint.

[0058] In the embodiment of the invention shown in the figures, the machine tool structure 10 comprises three stabilizing means and two drive members 16 arranged on each of its sides.

[0059] One of the advantages of the present invention lies in the modularity of the structure, in that it is possible to incorporate additional stabilizing means and drive components 16 without significant structural modifications to the machine tool. Such an arrangement allows, for example, the addition of a cutting or woodworking station upstream or downstream of the planing tool.

[0060] Structural modifications within the framework of an evolution of the machine tool, and therefore of the number of stabilizing means and drive elements 16, consist only of a possible modification of the upper frame 13 and the support base 11, or of a fixing of an additional frame and base.

[0061] In addition, it is also possible to easily increase the height travel limit of the tool carrier apron 15 in order to increase the cutting thickness of the planing tool, to adapt to the dimensions of the piece of wood to be planed, for example by only replacing the support columns 14 and the worm screws 160 with others having a greater length.

[0062] Thanks to the characteristics of the invention, the machine tool structure 10 allows for the simple, rapid evolution, without generating a substantial additional cost, of a machine tool comprising said structure.

[0063] In other words, the present invention makes it possible to change the cutting thickness limits of the machine tool according to the dimensions of the pieces of wood to be machined and to add cutting or processing stations for the pieces of wood, without modifying the tool holder apron 15, the machining table 12, any tool holders or motion transmission elements, thanks to the particular arrangement of the support columns 14 and the drive elements 16.

[0064] More specifically, the drive elements 16 and the stabilizing means being arranged on the sides of the machine tool structure 10 and not integrated into the machining table 12 and the tool apron 15, it is possible to modify or replace them so as to vary the limit parameters of the machine tool, such as the maximum stroke of the tool apron 15, without requiring further modifications to the structure of said machine tool.

[0065] Another advantage of the present invention lies in the fact that changing the support columns 14 and the worm gears 160 to obtain a greater stroke of the tool holder 15 does not result in a change in the minimum cutting thickness. That is to say, changing the support columns 14 and the worm gears 160 only affects the maximum cutting thickness.

[0066] Thanks to this advantage of maintaining the minimum cutting thickness of the machine tool, the said machine tool is particularly versatile and can machine pieces of wood of very diverse sizes.

[0067] Furthermore, the arrangement of the machine tool structure 10 according to the present invention allowing the movement of the tool apron 15 between the upper frame 13 and the machining table 12, the stroke of said tool apron 15 is significantly greater than that of the aprons of state-of-the-art machine tools.

Claims

1. Machine tool structure (10) comprising a frame comprising: - a bearing plate (11), - a work table (12) resting on said plate and over which the pieces of wood to be milled are intended to be conveyed, - an upper frame (13), - support columns (14) interposed between the bearing plate (11) and the upper frame (13), characterized in that the machine tool structure (10) further comprising a tool-holder apron (15) connected to translational drive members (16), interposed between said upper frame (13) and the bearing plate (11), and configured to slide the tool-holder apron (15) between the work table (12) and the upper frame (13), and stabilizing means formed by cylindrical sleeves (140) fitted freely translationally around support columns (14), said sleeves (140) being rigidly attached to carriages (163) rigidly attached to the tool-holder apron (15).

2. Machine tool structure (10) according to claim 1, wherein the translational drive members (16) are formed by electric cylinders each comprising a worm screw (160) attached by each of its ends respectively to the upper frame (13) and to the bearing plate (11), rotatably, said electric cylinders each further comprising a carriage (163) cooperating with the worm screw (160) by a helical link, said carriages (163) being attached to the tool-holder apron (15).

3. Machine tool structure of claim 2, wherein the worm gears (160) are rotated by angular gear devices arranged on the upper frame (13) and connected to each other by transmission shafts linked to an output shaft of an electric motor.

4. Machine tool structure of claim 1, wherein the stabilizing means comprise flanges, each flange being attached to one end of a sleeve (140) and having a through-hole through which a support column (14) extends.

5. Machine tool structure according to claim 1, wherein each carriage (163) is interposed between and mechanically connected to two adjacent sleeves (140), a support column (14) is arranged at each corner of the upper frame (13).