EP3919246A1 - Method for production of wooden dowels for glued wall plugs - Google Patents

Abstract

The invention relates to a method for the production of cylindrical wooden rods with cross grooves which are used for the production of glue dowels. The process has automatic, sequential operations. At the beginning, cylindrical smooth wooden rods (9) are produced by radial milling from wooden rods (2) with a square cross-section. In the following, cylindrical wooden rods (9) are produced by plastic roll deformation with three gears, cylindrical rods (10) which have spiral grooves inclined to the left on the surface. In the final phase, by plastic roll deformation, with three other gears, the wooden rods (10) with helical grooves inclined to the left are overlapped with helical grooves inclined to the right. The end product are wooden sticks (31) on the surface of which there is a network with crossed helical grooves. According to the invention, a device with three structural units (A), (B) and (C) is used to materialize the method and its work phases.

Description

The invention relates to a method for the production of cylindrical wooden rods which have a network of helical crossed grooves on the surface, produced by plastic roll deformation. The main application of these wooden rods is for the production of glue dowels for the furniture industry, in particular for the connection of furniture parts made of solid wood.

Wood glue dowels are auxiliary elements that are used in the furniture industry for rigidly connecting various furniture parts. The raw material for the production of wooden dowels are smooth or grooved cylindrical wooden rods, from which dowels of a given length are cut on automatic machines.

The requirements for wooden dowels relate to mechanical strength and to ensuring a long service life, which must at least correspond to the useful life of the furniture.

The mechanical strength is determined by the appropriate selection of the types of wood for the production of wooden rods from which the dowels are produced, by the suitable dimensioning of the dowels in terms of their diameter and length, as well as by ensuring a sufficient amount of glue, evenly distributed on the entire connection area, secured.

The durability of the glue depends on the size of the contact area between the wooden dowel and the glued furniture element, as well as on the type and quality of the glue used.

For the gluing of furniture elements of classic furniture with a pulpwood structure, cylindrical wooden dowels with a smooth surface, but also cylindrical wooden dowels with a longitudinally grooved surface, are currently used.

Smooth cylindrical rods for the production of glue dowels are obtained by parallel longitudinal milling of wooden slats. After the passage of a wooden slat between a router and a lower milling cutter, each of which has a cutting profile with several semicircles, four to eight cylindrical wooden sticks simultaneously result, corresponding to the width of the slat

Longitudinally grooved cylindrical wooden dowels are also obtained by longitudinal milling of wooden slats. The difference to the production of smooth cylindrical wooden rods is that the two milling cutters have toothed semicircles. The result is the simultaneous production of four to eight cylindrical wooden rods with parallel longitudinal grooves, the recess between two grooves being obtained by removing the wood material by cutting milling.

Although wooden dowels made from smooth cylindrical wooden rods have a larger contact area with the mounting holes in the furniture elements than dowels with longitudinally grooved contact surface, the latter are preferred, as the presence of grooves through the channels between the flanks brings a larger amount of glue into the connection area as cylindrical dowels with a smooth contact surface

For furniture made of solid wood, which require high-quality gluing, which in turn ensures high strength and durability, cylindrical wooden dowels with grooves, with diameters of 8 mm, 10 mm and 12 mm are used, the grooves being mainly produced by roll forming. For the production of this type of wooden dowel, long cylindrical wooden rods are used as the raw material, the surface of which is roll formed under a certain pressure using two processes.

In the first phase of a roll forming process, cylindrical wooden rods are produced from smooth wooden rods with a square cross-section with the help of rotary milling cutters, the diameter of which corresponds to the final diameter of the wooden dowels obtained from these rods.

In the second phase of this process, the smooth cylindrical wooden rods are plastically deformed on the surface with the help of two driven steel wheels, each with grooves arranged radially on a semicircle, the end products are wooden rods with parallel grooves, oriented lengthways.

In another method, known to the authors from their own document "Method for the production of wooden rods with cross grooves", file OSIM A0 / 218.27.04.202, in the first phase one also starts from smooth wooden rods with a square cross-section, which are milled into cylindrical smooth wooden rods are transformed, the diameter of which also corresponds to the prescribed diameter of the glue dowel.

In the second phase, these wooden rods are deformed, one after the other, between three or four cylindrical rotating gears. The result is a wooden stick, on the surface of which there are, created by plastic rolling deformation, helical grooves, the inclination of which is to the right or to the left.

Grooved dowels, produced from wooden rods, in which the grooves are obtained either by plastic longitudinal rolling deformation or by plastic helical rolling deformation of cylindrical smooth wooden rods, show in comparison to dowels
which the grooves are obtained by milling cylindrical smooth wooden rods have a better quality. This better quality results from the fact that for the dowels obtained by plastic roll deformation, water glue absorbed in the channels between the grooves swells shortly after the assembly of the furniture elements, thus causing an almost complete restoration of the initial diameter of the cylindrical shape. The contact and clamping surface of the furniture elements is therefore large compared to the grooved dowels produced by milling, since half of the dowel surface was removed from the latter by milling the cylindrical wooden rods.

Both the dowels with grooves produced by plastic roll deformation and dowels with longitudinally milled parallel grooves have a disadvantage, namely that when they are pressed into the furniture element, part of the glue, due to the slippage, under the pumping action of the pressed-in dowel, onto the surface increases.

However, there is a significant difference between cylindrical wooden rods with helical grooves, obtained by plastic rolling deformation, and wooden rods with parallel longitudinal grooves, also obtained by plastic rolling deformation. The dowels, produced from wooden rods with helical grooves, have a greater length of the channel between the flanks than the dowels produced from wooden rods with parallel grooves. Correspondingly, the amount of glue brought into the hatch is greater with the first than with the second. At the same time it causes the greater length of the channel between the flanks of the screw grooves a stronger braking of the movement of the glue to the furniture surface, as a result of the pumping action of the driven wooden dowel.

It is the object of the invention to provide a method by means of which high-quality wooden rods are secured for the simple, reliable and high-quality production of glued wood dowels.

The object achieved by the invention consists in the description of an automatic process for the production of cylindrical wooden rods which have a network of helical crossed grooves with a small pitch on the surface.

The process of making cylindrical wooden bars with cross grooves involves three successive stages.

In the first stage, wooden rods with a square cross-section are automatically fed from a magazine into a rotating milling cutter.

In the second stage, the wooden rods with a square cross-section are radially milled in order to transform them into cylindrical, smooth wooden rods. This operation is followed by a plastic rolling deformation of the surface of the cylindrical wooden rods, which leads to cylindrical wooden rods with helical grooves inclined to the left.

In the third stage, the wooden bars are additionally rolled with helical grooves inclined to the left. This additional deformation results in helical right-sloping grooves that are overlapped over the left-sloping grooves. The result is a network of helical cross grooves, with a small pitch, the grooves of which are inclined to the left and to the right. In this network, the peaks and depths of the channels, between the flanks of the grooves, are between 0.5 mm and 0.7 mm.

• Eine Einheit zur automatischen Versorgung des Vorschubs mit Holzstäben mit quadratischem Querschnitt
• Eine Einheit zum zylindrischen Fräsen und zur plastischen Walzerformung der zylindrischen Holzstäbe mit der Neigung der Rillen nach links
• Eine Einheit zur plastischen Walzerformung der zylindrischen Holzstäbe mit der Neigung der Rillen nach links um diesen nach rechts geneigte Rillen zu überlappen.

The automatic machine equipment which materializes the method according to the invention has all the work processes in a continuous flow and consists of three basic units:

• A unit for the automatic supply of the feed with wooden rods with a square cross-section
• A unit for cylindrical milling and plastic roll forming of the cylindrical wooden rods with the inclination of the grooves to the left
• A unit for plastic roll forming of the cylindrical wooden rods with the inclination of the grooves to the left in order to overlap these grooves inclined to the right.

The supply unit is exchangeable and serves to ensure an automatic and continuous feed of the wooden rods with a square cross-section in the direction of the milling and plastic roll forming unit. The supply unit comprises a gravity feed magazine, a pneumatic feed cylinder and a guide with a square cross-section. Interchangeability is ensured with three different supply units for wooden bars with the sides of the square passage of 9 mm, 11 mm and 13 mm, which correspond to the final diameters of 8 mm, 10 mm and 12 mm for wooden bars with crossed grooves.

To prevent the wooden sticks from jamming in the gravity feed magazine, all wooden sticks must have a length of 800 mm. The pneumatic feed cylinder is part of an electropneumatic control circuit that includes a roller limit switch, a solenoid valve and a Includes microprocessor. The feed rod of the pneumatic feed cylinder pushes the first wooden rod, with a square cross-section, out of the feed magazine into an exchangeable steel guide, with an axial supply and a pyramid-shaped inlet, whose passage channel also has a square cross-section and whose side dimension is 0.5 mm larger than the dimension of a Side of the wooden stick. In the following, the push rod pushes the wooden stick, with a square cross-section, into the radial milling cutter, which transforms it into a cylindrical wooden stick.

In order to ensure the feed of the wooden rod with a square cross-section, the stroke of the feed rod must be sufficient until its cylindrically milled beginning enters the gap between three gears, which in turn, through plastic rolling deformation, on the surface of the wooden rod, helical grooves with the inclination to the left, produce. From the moment the beginning of the cylindrically milled wooden stick is gripped by the three cogwheels, these also develop a tensile force, which drives the wooden stick with a square cross-section in the direction of the cutter and, at the same time, the feed of the cylindrically milled part of the wooden stick Direction of the second plastic roll deformation unit, secures. The stroke of the push rod is monitored by the electronic control. During the time in which the wooden stick with a square cross-section moves linearly in the direction of the cutter, the sensing roller of the electrical limit switch is in contact with one side, the stick with a square cross-section. After the end of the wooden rod with square cross-section has passed the sensing roller of the electrical limit switch, caused by the continuous feed, this activates the microprocessor, which in turn secures the air supply to the pneumatic cylinder via the electro valve and pulls the feed rod back into the starting position. In the following, a new supply of the milling cutter with a wooden stick with a square cross-section is ensured via the automatic cycle.

The operator's role consists only in the periodic supply of the wooden stick storage and intervention, through the window of the wooden stick storage, in the situation in which the gravitational feed of the wooden sticks with a square cross-section is blocked in the storage. The operator does not have to constantly monitor the advancement of the wooden sticks in the store, since a possible stowage of the wooden sticks is detected by the electronic control, which immediately triggers an acoustic and visual alarm.

In the first part, the cylindrical milling and plastic rolling deformation unit implements the cylindrical milling of the wooden rods with a square cross-section and in the second part of the unit the plastic rolling deformation of the cylindrical wooden rods, which subsequently have helical grooves on the surface with a small pitch, inclined to the left. For this purpose, the unit has a radial milling cutter, which is interchangeable depending on the diameter of the cylindrical rod to be machined and which is screwed onto a steel drive pulley. On the back of the drive plate are three cylindrical gear wheels, made of hardened steel, with a small module, which are mounted on radial bearings and achieve plastic rolling deformation on the surface of the cylindrical wooden rod. The three gears are positioned radially at an angle of 120 ° and form a gap between them, in which an equilateral triangle can be inscribed, at the same time the axis of rotation of the gears forms an angle of 15 ° with the axis of symmetry of the processed wooden rods, inclined to the left.

For a certain diameter of a finished wooden stick, which is a network of crossed grooves has, both for the first and for the second plastic roll deformation unit, the condition must be met that between the sides of the triangle formed between the three gears, a circle with a diameter that is 1.2 mm smaller than the prescribed The diameter of the finished wooden stick can be inscribed. The center of this circle must coincide exactly with the axis of rotation of the milling cutter. The condition with regard to the circle inscribed in the triangle must be fulfilled at every transition to a different machining diameter of the cylindrical wooden stick. In order to ensure the adaptation to the three different machining diameters, the axis of symmetry of the cylindrical bearing axis of the three radial ball bearings of the roll forming gearwheels is offset by 3 mm from the axis of symmetry of the assembly cone. This adaptation ensures an eccentric movement of the gears, which enables the approximation or the distance of the gears from the wooden stick to be achieved by the rotation around the axis of symmetry of the cones. For this purpose, when setting a new diameter, a cylindrical gauge made of hardened and ground steel is used, the diameter of which is 1.2 mm smaller than the diameter of the end wooden rod, which has a network of crossed grooves on the surface. The gauge is inserted through the cylindrical passage of the milling cutter until it is between the three gears. The adjustment and alignment is done by loosening the conical clamping nuts of the three gears followed by their rotation around the cone axis of symmetry until they touch the surface of the gauge. At this point the setting is complete and the taper lock nuts are tightened.

The second roll plastic deformation unit creates helical right-inclined grooves, these being overlapped with those left-inclined grooves created with the first roll plastic deformation unit. Apart from two differences, this unit, in terms of size and geometry, is identical to the first unit. The first difference is that instead of the milling cutter in the front part, this unit has an exchangeable, depending on the diameter of the cylindrical rod to be machined, a cylindrical guide with an axial supply and a frustoconical inlet. The second difference is that the three gears have an angle of inclination of 15 ° to the right, compared to the three gears of the first unit which have this angle of inclination of 15 ° to the left.

Due to the engagement in the surface of the cylindrical wooden rod, each roller in the two plastic roll deformation units performs a rotary movement around its own axis and a planetary movement around the cylindrical wooden rod. Under these conditions, the gears work together with the wooden rod to be processed to form a screw-nut arrangement (cylindrical gears - nut, cylindrical wooden rod - screw). After the feed rod of the pneumatic cylinder has been withdrawn, this arrangement develops a tensile force that is sufficient to feed the remaining part of the wooden rod, with a square cross-section, in the direction of the milling cutter, at the same time as the advance of the cylindrically milled part of the wooden rod, in the direction of the second roll forming unit to secure.

The gears of the second plastic roll deformation unit develop an identical tensile force with the force exerted in the first unit. After leaving the first plastic roll deformation unit, the longitudinal feed of the wooden rod, for the purpose of plastic deformation, made only by the three gears of the second roll forming unit, these continuing the advance until the wooden stick crosses the three gears. After leaving the gears, the wooden stick rotates freely in the cylindrical cavity of the hollow shaft of the drive motor until it is pushed out by the next wooden stick with crossed grooves.

After leaving the second plastic roll deformation unit, the wooden rods fall into a collecting trolley, from where they reach a machine for cutting and chamfering automatic wooden dowels with predetermined lengths, which are chamfered at the ends at 1x45 ° and which have a network of helical shapes on the cylindrical surface Have cross grooves.

• Die Kanäle der gekreuzten schraubförmigen Rillen treffen sich auf der Oberfläche der zylindrischen Holzdübel, die aus Holzstäben mit gekreuzten schraubförmigen Rillen gefertigt werden, in entgegengesetzten Winkeln. Dieses bewirkt, dass die Ausströmrichtung des Leims, aus den Kanälen zwischen den Rillen, unter der Kolbenwirkung des Dübels, beim Einführen in das zylindrische Loch des Möbelelementes, bei jeder Kreuzung der Rillen in entgegengesetzter Richtung erfolgt. Dadurch wird verhindert dass der Leim in grossem Mass auf die Oberfläche des Möbelelementes austritt;
• Das durch kreuzförmige Rillen gebildete Netzwerk führt zu einer gleichmäßigen Verteilung des Leims über die gesamte Oberfläche des Holzdübels und auf der zylindrischen Innenoberfläche der Klebestelle des verleimten Möbelteiles;
• Kreuzrillen, bringen eine größere Menge an Leim in die Verbindungszone als parallele Rillen, dass sich günstig auf die Festigkeit und Haltbarkeit der Leimverbindung auswirkt;
• Leime auf Wasserbasis, die zur Verbindung von Möbelelementen mit Holzdübeln verwendet werden, führen dazu, dass nach dem Benetzen der Oberfläche des Holzdübels diese zeitlich quellen und eine fast glatte zylindrische Form annehmen, was sich ebenfalls günstig auf die mechanische Festigkeit und Haltbarkeit der Verleimung, führt.
• Im Folgenden ist eine Ausführungsform der Erfindung, in Verbindung mit Fig.1, Fig. 2, Fig.3, Fig.4, Fig.5, Fig.6 und Fig.7, gezeigt, die Folgendes darstellen:
• Fig.1. Blockschaltbild der Herstellung von Holzstäben mit gekreuzten Rillen erhalten durch plastische Walzverformung mit Zahnrädern; Fig.2. Ansichten der plastischen Walzverformungsstruktur mit Zahnrädern; Fig.3. Ansicht eines Zahnrades zur Walzverformung; Fig.4. Ansicht der Stützelemente eines Zahnrades zur Walzverformung; Fig.5. Vorderansicht der Versorgungseinheit; Fig.6. Ansicht von oben und Schnitt der zylindrischen Fräs- und plastischen Walzverformungseinheit für die Erzeugung zylindrischer Holzstäbe mit nach links geneigten schraubenförmigen Rillen; Fig.7 Ansicht von oben und Schnitt der zylindrischen Fräs- und plastischen Walzverformungseinheit für die Erzeugung zylindrischer Holzstäbe mit nach rechts geneigten schraubenförmigen Rillen

The advantages of the invention are that a network of screw-shaped cross grooves on the surface of glue dowels, produced from cylindrical wooden rods roll-formed on the surface, according to the invention, on the one hand ensures an increased and even amount of glue when connecting the furniture elements and on the other hand pushes out the glue, when inserting the dowel into the wooden part to be connected, is greatly reduced. These benefits are achieved by:

• The channels of the crossed helical grooves meet at opposite angles on the surface of the cylindrical wooden dowels, which are made from wooden rods with crossed helical grooves. This causes the outflow direction of the glue, from the channels between the grooves, under the piston effect of the dowel, when it is inserted into the cylindrical hole of the furniture element, in the opposite direction at each intersection of the grooves. This prevents the glue from escaping to a large extent on the surface of the furniture element;
• The network formed by cross-shaped grooves leads to a uniform distribution of the glue over the entire surface of the wooden dowel and on the cylindrical inner surface of the glue point of the glued furniture part;
• Cross grooves, bring a larger amount of glue into the connection zone than parallel grooves, which has a positive effect on the strength and durability of the glue connection;
• Water-based glues, which are used to connect furniture elements with wooden dowels, mean that after the surface of the wooden dowel is wetted, it swells over time and takes on an almost smooth cylindrical shape, which also has a positive effect on the mechanical strength and durability of the glue .
• The following is an embodiment of the invention, in conjunction with Fig.1 , Fig. 2 , Fig. 3, Fig. 4 , Fig. 5 , Fig. 6 and Fig.7 , which represent the following:
• Fig.1 . Block diagram of the production of wooden bars with crossed grooves obtained by plastic roll deformation with gear wheels; Fig. 2 . Views of the plastic roll deformation structure with gears; Fig. 3 . View of a gear for rolling deformation; Fig. 4 . View of the support elements of a gear for rolling deformation; Fig. 5 . Front view of the supply unit; Fig. 6. View from above and section of the cylindrical milling and plastic roll forming unit for the production of cylindrical wooden rods with helical grooves inclined to the left; Fig.7 Top view and section of the cylindrical milling and plastic roll forming unit for the production of cylindrical wooden rods with helical grooves inclined to the right

The device that materializes the method according to the invention consists of three basic units: an exchangeable supply and feed unit A, a unit B for cylindrical milling and plastic rolling deformation and a unit C for plastic rolling deformation.

The supply and feed unit A contains a bearing 1 with a gravity feed for wooden rods 2 with a square cross-section, provided with a window f for inspection and decongestion, an exchangeable guide body 3 with a square cross-section and a truncated pyramid-shaped inlet, a pneumatic feed cylinder 4 with a feed rod 5 , an electric valve 6, a microprocessor 7 and an electric limit switch 8 with a contact roller and an inductive sensor 8a. '

The milling unit B for cylindrical milling and plastic rolling deformation converts, in the first phase, the wooden rods 2 with a square cross-section into cylindrical, smooth wooden rods 9 . In the second phase, these wooden rods are converted into cylindrical rods 10 by means of plastic surface rolling deformation, which have helical grooves on their surface, with a small pitch, inclined to the left. The unit B consists of a drive pulley 11 made of steel, which is mounted with screws on a steel housing 12 , which in turn is screwed to the front of a hollow shaft 13, an electric drive motor 14, rotating to the left. The hollow shaft 13 is axially drilled cylindrically along its entire length and has guide body 15 with a frustoconical inlet on the rear part, which can be exchanged depending on the diameter of the wooden rods 10. A radial milling cutter 16, which can be exchanged depending on the prescribed diameter of the cylindrical wooden rods 9, is screwed onto the front of the steel drive pulley 11. On the back of the drive pulley 11 there is a group of gear wheels 17, 18 and 19 with a small module, which are used for plastic roll deformation. The gears each have a diameter of 32 mm, a number of 60 teeth and a width of 12 mm and create helical grooves with a channel depth between the flanks of the grooves of 0.5 to 0.7 mm and are radial at an angle of 120 ° mounted. Each gear for rolling deformation has an inclination of 15 ° between its axis of rotation and the axis of symmetry of the processed wooden rod. The three gears are each mounted on a radial bearing 20 which is locked against axial displacement with two Seeger rings 21 and 22. In turn, the inner ring of each bearing is screwed to the corresponding cylindrical shafts 26 with three nuts 23, 24 and 25. The cylindrical axes 26 are extended with three conical axes 27 , which in turn are screwed to the steel drive pulley 11 with three nuts 28, 29 and 30. In order to adjust the diameter of the plastic, roll-formed wooden rods 10 with the helical grooves inclined to the left, the axis of symmetry of the cylindrical axes 26 is offset three millimeters from the axis of symmetry of the conical axes 27. The plastic rolling deformation unit C produces cylindrical wooden rods 31 with crossed helical grooves, which are created from the overlap of the helical grooves inclined to the left with the group of gears 17, 18 and 19, the rolling deformation unit B, with the helical grooves inclined to the right with a group of Zanhrädern 32,33 and 34, the roll-forming unit C, arise. The conical axes 27 of the unit C are screwed tight with three nuts 35, 36 and 37 on the rear side of the drive pulley 38, the inner rings of the radial bearings 20 being tightened with three other nuts 39, 40 and 41

The unit C has to secure an exchangeable guide body 42 with a frustoconical inlet for the sliding guidance of the wooden rods 10 with helical grooves inclined to the left in the front part. The unit C also includes a steel housing 43 which is screwed to the hollow shaft 44 of an electric drive motor 45, rotating to the right. The hollow shaft 44 is cylindrical-centrically bored over its entire length and has a threaded, replaceable guide body 46 with a frustoconical inlet on the rear side.

In order to set the plastic deformation diameter for the plastically deformed wooden rods and for unit C , the symmetry axis of the three cylindrical axes 26 is also offset by three millimeters from the symmetry axis of the three conical axes 27 in this roll-forming unit. The three gears of unit C have an inclination angle of 15 ° which is opposite to the inclination angle of 15 ° of the three gears of unit B.

1. a) Manuelles Laden des Lagers 1, der Einheit A, mit Schwerkraftzufuhr mit Holzstäben 2, mit quadratischem Querschnitt. Die Holzstäbe fallen der Reihe nach in einem Führungskanal von wo sie pneumatisch von der Vorschubstange 5 durch den Führungskörper 3 zum Radialfräser 16 gedrückt werden. Die pneumatische Bewegung der Vorschubstange 5 setzt sich fort, bis das Ende des Holzstabstabs 9 in den leeren axialen Raum zwischen der Gruppe der Zahnräder 17,18 und 19 gelangt. Entsprechend dem Hubende wird die Vorschubstange 5 automatisch, in die Ausgangsposition zurückgezogen bis der Endschalter 8 den Verbrauch des ersten Holzstabs 2 meldet. In diesem Moment setzt der Mikroprozessor 7 das Magnetventil 6 unter Spannung, dieses lässt seinerseits Druckluft in den Pneumatikzylinder 4, und die Vorschubstange 5, versorgt den Radialfräser 16 mit einem folgenden Holzstab 2 mit quadratischem Querschnitt.
2. b) Fräsen der Holzstäbe 2, mit quadratischem Querschnitt, in der Einheit B, mit dem Radialfräser 16, um zylindrische glatte Holzstäbe 9 zu erhalten.
3. c) Plastische Walzverformung, in der Einheit B, der zylindrischen Holzstäbe 9, um Holzstäbe 10, mit den nach links geneigten schraubenförmigen Rillen, in einer Tiefe von 0,5 mm bis 0,7 mm, zu erhalten. Die Walzverformung erfolgt mit der Gruppe der Zahnräder 17,18 und 19 die auf der Antriebscheibe 11 aus Stahl montiert sind die mit einer Geschwindigkeit von 700 U/min, von dem elektrischen Antriebmotor 14, nach links gedreht wird.
4. d) Plastische Walzverformung, in der Einheit C, der zylindrischen Holzstäbe 10, mit schraubenförmigen nach links geneigten Rillen, um Holzstäbe 31 mit nach rechts geneigten schraubenförmigen Rillen, in einer Tiefe von 0,5 mm bis 0,7 mm, zu erhalten, Die Walzverformung in der Einheit C erfolgt mit der Gruppe von drei Zahnräder 32,33 und 34, die auf einer anderen der Antriebscheibe 38 aus Stahl montiert sind und die auch mit einer Geschwindigkeit von 700 U/min, von einem elektrischen Antriebmotor 41, nach rechts gedreht wird. Durch die Überlappung der nach links geneigten Rillen mit den nach rechts geneigten Rillen weisen die zylindrischen Holzstäbe 31, auf ihrer Oberfläche, ein Netz gekreuzter nach links und nach rechts geneigten schraubenförmiger Rillen, auf. Die Zahnräder 17,18,19,32,33 und 34, alle zur plastischen Walzverformung bestimmt, erreichen aufgrund der Drehbewegung der Antriebscheiben 11, und aus Stahl, auf denen sie montiert sind, und durch ihren Kontakt mit den zu bearbeitenden Holzstäben 9 und 10, eine Planetenbewegung, gegeben durch die Drehung um ihre eigene Symmetrieachse und eine Drehung um den Holzstab. Die Planetenbewegung bewirkt, dass die Zahnräder 17,18 und 19, die mit dem Holzstab in Kontakt stehen, als ein der Mutter- Schrauben - System funktioniert dass eine Vorschubkraft entwickelt die ausreicht, um die Holzstäbe 2 mit einem quadratischen Querschnitt durch den Radialfräser 16 zu ziehen, nachdem sich die Vorschubstange 5 für einen neuen Vorschub zurückgezogen hat, Die gleiche Vorschubkraft sichert auch die Übernahme der Holzstäbe 10, mit schraubenförmigen Rillen nach links geneigt, zwischen die Zahnräder 32,33 und 34, welche schraubenfürmige, nach rechts geneigte, Rillen auf diese Holzstäbe aufbringen. Sobald die Holzstäbe 10 von diesen Zahnrädern aufgenommen werden, entwickelt deren Planetenbewegung auch eine Vorschubkraft, die sowohl den Vorschub der Holzstäbe 10 als auch den Vorschub der Holzstäbe 31 sichert bis das Ende der Letzteren, den Zahnradeingriff verlässt. Im Folgenden dreht sich der fertige Holzstab 31 frei in der Hohlwelle 44 bis der Vorschub des nächsten Holzstabes 31 diesen Holzstab, durch den austauschbarer Führungskörper 42 mit kegelstumpfförmigem Einlass, drückt. Die fertigen Holzstäbe, mit einem Netz von schraubförmigen Rillen, fallen in einen Transportwagen, von wo sie zu einer automatischen Dübelzuschneid- und Dübelanfasmaschine gelangen.

The method according to the invention consists of the following processing operations:

1. a) Manual loading of warehouse 1, unit A, with gravity feed with wooden bars 2, with a square cross-section. The wooden sticks fall one after the other into a guide channel, from where they are pneumatically pressed by the feed rod 5 through the guide body 3 to the radial milling cutter 16. The pneumatic movement of the feed rod 5 continues until the end of the wooden stick 9 enters the empty axial space between the group of gears 17, 18 and 19 . According to the end of the stroke, the feed rod 5 is automatically withdrawn into the starting position until the limit switch 8 reports the consumption of the first wooden stick 2. At this moment, the microprocessor 7 energizes the solenoid valve 6 , which in turn lets compressed air into the pneumatic cylinder 4, and the feed rod 5 supplies the radial milling cutter 16 with a following wooden rod 2 with a square cross-section.
2. b) Milling the wooden rods 2, with a square cross-section, in unit B, with the radial milling cutter 16 in order to obtain cylindrical, smooth wooden rods 9 .
3. c) Rolling plastic deformation, in the unit B, of the cylindrical wooden rods 9 to obtain wooden rods 10 with the helical grooves inclined to the left, at a depth of 0.5 mm to 0.7 mm. The rolling deformation is effected with the group of gears 17,18 and 19 which are mounted on the drive pulley 11 made of steel that is at a speed of 700 rev / min, rotated by the electric drive motor 14 to the left.
4. d) Plastic rolling deformation, in the unit C, of the cylindrical wooden bars 10, with helical grooves inclined to the left, to obtain wooden bars 31 with helical grooves inclined to the right, at a depth of 0.5 mm to 0.7 mm, Die Roll deformation in the unit C takes place with the group of three gears 32,33 and 34, which are mounted on another of the drive pulley 38 made of steel and which are also rotated to the right at a speed of 700 rpm, by an electric drive motor 41 will. By overlapping the grooves inclined to the left with the grooves inclined to the right, the cylindrical wooden rods 31 have, on their surface, a network of crossed helical grooves inclined to the left and to the right. The gears 17, 18, 19, 32, 33 and 34, all intended for plastic roll deformation, reach 9 and 10 due to the rotary movement of the drive disks 11 and made of steel on which they are mounted and due to their contact with the wooden rods to be machined , a planetary motion given by the Rotation around its own axis of symmetry and a rotation around the wooden stick. The planetary motion causes the gears 17, 18 and 19, which are in contact with the wooden rod, to function as a nut-screw system that develops a feed force that is sufficient to allow the wooden rods 2 with a square cross-section through the radial cutter 16 to be after the feed rod 5 has withdrawn for a new feed, the same feed force also ensures the takeover of the wooden rods 10, with helical grooves inclined to the left, between the gears 32, 33 and 34, which have helical grooves inclined to the right apply these wooden sticks. As soon as the wooden rods 10 are picked up by these gears, their planetary motion also develops a feed force which ensures both the advance of the wooden rods 10 and the advance of the wooden rods 31 until the end of the latter leaves the gear mesh. The finished wooden stick 31 then rotates freely in the hollow shaft 44 until the advance of the next wooden stick 31 pushes this wooden stick through the exchangeable guide body 42 with a frustoconical inlet. The finished wooden sticks, with a network of screw-shaped grooves, fall into a trolley, from where they are transferred to an automatic dowel cutting and chamfering machine.

Claims (7)

Process for the production of wooden sticks for glue dowels, in which six gear wheels, a pneumatic cylinder, an electric valve, a roller limit switch and two electric motors are used, characterized in that to produce high quality cylindrical wooden sticks for the production of glue dowels, on the surface of which there are helical grooves , with a small pitch, cross, for the realization of which one cutting and two plastic rolling deformations are used, in which all processes take place automatically, in a continuous flow, by producing cylindrical wooden rods (9) from wooden rods (2) with a square cross-section which afterwards, in a first plastic rolling deformation, cylindrical rods (10), which on the surface have helical grooves with a small pitch, with the grooves inclined to the left, and in a subsequent second plastic rolling deformation the wooden rods (10), helical grooves , with a small slope, with the R be inclined to the right, overlapped, produced, the result are cylindrical wooden rods (31) on the surface of which there is a network of crossed, helical grooves, the implementation of the method takes place, according to the invention, with three units mounted in series, ( A), (B) and (C). Process for the production of wooden sticks for glue dowels according to claim 1, characterized in that it has a work flow in the following order: a) Automatic feeding, from the unit (A), of a wooden stick (2), with a square cross-section, to a radial milling cutter ( 16), belonging to unit (B); b) milling the wooden stick (2) with a square cross-section to form a cylindrical wooden stick (9); c) rolling deformation of the surface of the cylindrical wooden rod (9), at the same time as securing its automatic feed, in order to obtain wooden rods (10) having on the surface helical grooves with a small pitch, the inclination of which is to the left; d) Plastic roll deformation, in the unit (C), of the wooden rod (10), with helical grooves inclined to the left, with three other gears to obtain a wooden rod with helical grooves on the surface, the inclination to the right the latter, the grooves inclined to the left, being overlapped, the end result is a cylindrical wooden rod (31), for glue dowel production, having on its surface a network of crossed, helical, grooves. Method for the production of wooden rods for glue dowels, according to claim 1 and claim no. 2, characterized in that for the production of a cylindrical wooden rod (9) the wooden rod (2) with a square cross-section, from the feed rod (5) into a radial milling cutter (16) , is pressed, whereby after milling from the wooden stick (2), with a square cross-section, a cylindrical wooden stick (9) is created. Process for the production of wooden rods for glue dowels, according to claim 1, claim no. 2, and claim no. 3, characterized in that the cylindrical smooth wooden rod (9) with the The feed rod (5) is pushed into the gap between three gears (17), (18) and (19), which in turn leads to the plastic rolling deformation of the cylindrical wooden rod (9) , and at the same time, according to the screw-nut principle, to continuous longitudinal feed of the remaining part of the wooden rod (2) with a square cross-section, the part of the cylindrical already milled part of the wooden rod (9), as well as the deformed part of the wooden rod (10), in the direction of the unit (C). Method for producing wooden rods for glue dowels, according to claim 1, claim 2 and claim 3, characterized in that the end position of the stroke of the feed rod (5), detected by the inductive sensor (8a) at the right end of the pneumatic cylinder (4 ), corresponding to the moment in which the cylindrical wooden stick (9) is detected by the gears (17), (18) and (19) , this sensor activates the microprocessor (7) , which in turn controls the solenoid valve (6) that Compressed air enters the pneumatic cylinder (4) , and as a result, the retraction of the feed rod (5) into the ready position causes the feed rod (5) to remain in this position until the electric roller limit switch (8), the lack of the wooden rod (2) , with a square cross-section, caused by the continuous longitudinal advance of the cylindrical part of the wooden rod (9), by means of the gears (17), (18) and (19), recognizes, activates the microprocessor (7) anew, which in turn vo mn anew controls the solenoid valve (6) , which lets compressed air into the pneumatic cylinder (4) for the purpose of initiating a new feed for a subsequent wooden stick (2) with a square cross-section. Method for the production of wooden sticks for glue dowels, according to claim 1, claim no. 2 and claim no. 3, characterized in that the cylindrical wooden stick (10), with helical grooves inclined to the left, is inserted into the guide body (15) of the unit (C ), and further into the gap between the gears (32), (33) and (34) made of hardened steel and small module, which causes an additional plastic rolling deformation of the surface of the wooden rod ( 10 ), under the shape of helical inclined to the right Grooves, caused, at the same time, the gears (32), (33) and (34) also ensure the automatic longitudinal feed, according to the screw-nut principle, of the remaining part of the wooden stick (10) and the part of the already roll-formed part of the wooden stick ( 31), on the surface of which there is a network of crossed, helical grooves, which in the following, through the automatic, continuous longitudinal feed, through the exchangeable cylindrical guide (46) of the hollow w elle (44), is removed. Method for the production of wooden rods for glue dowels, according to claim no. 1 and claim no. 3, claim no. 4, claim no. 5 and claim no. 6, characterized in that, that the gears (17), (18), (19), (32), (33) and (34), are used for the plastic roll deformation of wooden rods and for their longitudinal feed, are made of hardened steel, a cylindrical shape with parallel teeth and a small module, a diameter of 32 mm, a number of 60 teeth, a width of 12 mm, and generate helical grooves whose channel depth is between 0.5 and 0.7 mm, three of the said gear wheels are radial mounted at an angle of 120 °, the gear wheels (17), (18) and (19) between their axis of rotation and the axis of symmetry of the cylindrical wooden rod (9) have an inclination of 15 ° to the left, and the gear wheels (23), ( 24) and (25), between their axis of rotation and the axis of symmetry of the wooden rod (31) have an inclination of 15 ° to the right.

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