EP3919246A1 - Procédé de fabrication de tiges en bois pour chevilles à coller - Google Patents

Procédé de fabrication de tiges en bois pour chevilles à coller Download PDF

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Publication number
EP3919246A1
EP3919246A1 EP20000206.1A EP20000206A EP3919246A1 EP 3919246 A1 EP3919246 A1 EP 3919246A1 EP 20000206 A EP20000206 A EP 20000206A EP 3919246 A1 EP3919246 A1 EP 3919246A1
Authority
EP
European Patent Office
Prior art keywords
wooden
cylindrical
rod
rods
grooves
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP20000206.1A
Other languages
German (de)
English (en)
Inventor
Gheorghe Gutt
Mihai Dimian
Valentin Popa
Amariei Sonia
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Universitatea Stefan Cel Mare din Suceava
Original Assignee
Universitatea Stefan Cel Mare din Suceava
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Universitatea Stefan Cel Mare din Suceava filed Critical Universitatea Stefan Cel Mare din Suceava
Priority to EP20000206.1A priority Critical patent/EP3919246A1/fr
Publication of EP3919246A1 publication Critical patent/EP3919246A1/fr
Pending legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27M—WORKING OF WOOD NOT PROVIDED FOR IN SUBCLASSES B27B - B27L; MANUFACTURE OF SPECIFIC WOODEN ARTICLES
    • B27M1/00—Working of wood not provided for in subclasses B27B - B27L, e.g. by stretching
    • B27M1/02—Working of wood not provided for in subclasses B27B - B27L, e.g. by stretching by compressing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27C—PLANING, DRILLING, MILLING, TURNING OR UNIVERSAL MACHINES FOR WOOD OR SIMILAR MATERIAL
    • B27C5/00—Machines designed for producing special profiles or shaped work, e.g. by rotary cutters; Equipment therefor
    • B27C5/08—Rounding machines
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27M—WORKING OF WOOD NOT PROVIDED FOR IN SUBCLASSES B27B - B27L; MANUFACTURE OF SPECIFIC WOODEN ARTICLES
    • B27M3/00—Manufacture or reconditioning of specific semi-finished or finished articles
    • B27M3/28—Manufacture or reconditioning of specific semi-finished or finished articles of dowels or bolts

Definitions

  • 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.
  • cylindrical wooden dowels with a smooth surface 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.
  • 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.
  • 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.
  • long cylindrical wooden rods are used as the raw material, the surface of which is roll formed under a certain pressure using two processes.
  • 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.
  • 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.
  • 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.
  • 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.
  • wooden rods with a square cross-section are automatically fed from a magazine into a rotating milling cutter.
  • 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.
  • 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.
  • the peaks and depths of the channels, between the flanks of the grooves are between 0.5 mm and 0.7 mm.
  • 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.
  • 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.
  • 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.
  • 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.
  • the sensing roller of the electrical limit switch is in contact with one side, the stick with a square cross-section.
  • the microprocessor secures the air supply to the pneumatic cylinder via the electro valve and pulls the feed rod back into the starting position.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • the gears work together with the wooden rod to be processed to form a screw-nut arrangement (cylindrical gears - nut, cylindrical wooden rod - screw).
  • 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.
  • 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.
  • 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.
  • the wooden rods 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.
  • 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 .
  • 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.
  • 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.
  • 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 Zanhizan 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.
  • 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.

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Forests & Forestry (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
EP20000206.1A 2020-06-02 2020-06-02 Procédé de fabrication de tiges en bois pour chevilles à coller Pending EP3919246A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP20000206.1A EP3919246A1 (fr) 2020-06-02 2020-06-02 Procédé de fabrication de tiges en bois pour chevilles à coller

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP20000206.1A EP3919246A1 (fr) 2020-06-02 2020-06-02 Procédé de fabrication de tiges en bois pour chevilles à coller

Publications (1)

Publication Number Publication Date
EP3919246A1 true EP3919246A1 (fr) 2021-12-08

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ID=72242899

Family Applications (1)

Application Number Title Priority Date Filing Date
EP20000206.1A Pending EP3919246A1 (fr) 2020-06-02 2020-06-02 Procédé de fabrication de tiges en bois pour chevilles à coller

Country Status (1)

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EP (1) EP3919246A1 (fr)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2681086A (en) * 1951-10-15 1954-06-15 Hans Heid Device for the manufacture of round corrugated wooden rods

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2681086A (en) * 1951-10-15 1954-06-15 Hans Heid Device for the manufacture of round corrugated wooden rods

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
"Verfahren zur Herstellung von Holzstäben mit Kreuzerillen", AKTE OSIM AO/218.27.04.202

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