EP0393384B1 - Apparatus for jointing veneer - Google Patents

Description

The invention relates to a device for assembling veneers with a plurality of transport rollers arranged on a drive shaft and at least one counter-pressure roller arranged parallel to this, a heating device and a pressing device. Such a device is known from DE-A-2 523 110.

Another similar device is known from DE-A-34 09 178. Devices of this type are used to glue individual veneers or strips of veneer lengthwise to one another in order to produce a large-area veneer sheet. Since the veneer workpieces to be processed later have large, but very thin sheets, it is necessary to position the individual veneers exactly against each other before the gluing takes place. It is necessary to position the edges to be glued exactly relative to each other over their entire length. It is known from the prior art to use a stop for this purpose, against which the individual veneer strips are conveyed. Particularly in the case of wavy veneer strips or conveyed at an angle to the direction of gluing, it is associated with considerable difficulties or in many cases completely impossible in the known machines to position the veneers.

Another veneer gluing machine is known from DE-C-747 289. In this machine, driving shafts of rotating belts or chains for feeding veneers are provided with slip clutches. The slip clutches can be designed, for example, as sprockets.

The invention has for its object to provide a device of the type mentioned which, with a simple structure and reliable operability, ensures transport and alignment of even the thinnest veneers with uneven longitudinal edges so that the longitudinal edges are aligned transversely to the direction of flow in a desired gluing direction can.

According to the invention, this object is achieved in a device of the aforementioned type by the characterizing features of claim 1.

The device according to the invention is distinguished by a number of considerable advantages. Due to the possibility of changing the diameter of an internal drive device, it is possible on the one hand to vary the contact pressure in the glue joint against the previous veneer sheets according to the respective requirements, and on the other hand to vary this contact pressure if veneers of varying thickness or different friction values are to be processed. According to the invention, the possibility of changing the diameter and allowing slippage, for example by means of a slip clutch, also leads to different conveying speeds or paths of the individual areas of the veneer or of the veneer sheet, so that veneers inserted obliquely or obliquely are aligned in a particularly simple manner can. There is no danger, as in the prior art, that leading areas of the veneer are pressed against a stop or against the rear edge of the previous veneer and be damaged, since the alignment of the adhesive edge of the veneer can be done by the transport and pressure rollers. It is particularly advantageous according to the invention that the rotational speed of the shaft carrying these transport rollers does not have to be changed, so that complicated controls can be dispensed with. By simply changing the pressure medium pressure, the internal force of the internal devices can be changed differently, so that different conveying speeds can be achieved in the individual areas of the device by means of a single drive.

In a particularly favorable further development of the invention it is provided that this transport and pressure roller is surrounded by an outer jacket made of an elastic material, which is held by means of a cylindrical carrier body inserted into the transport and pressure roller.

According to the invention, the transport and pressure roller is constructed in such a way that it receives a support cylinder with a central recess for carrying out a shaft and that in at least one area of the support cylinder a recess for transmitting the pressure of the pressure fluid to one acting on the jacket from the inside is preferred curved pressure plate is formed.

In order to distribute the supplied pressure fluid evenly over the respective length of the transport and pressure roller and to expose the jacket to a frictional force in a uniform manner, the invention provides that the support cylinder has an inner elastic hose in the region of the recess takes up, the inner wall of which can be acted upon by the pressure fluid. The hose thus serves on the one hand to seal and on the other hand to evenly transmit the pressure applied by the pressure fluid.

In a particularly preferred embodiment of the invention it is further provided that the hose extends only over part of the length of the support cylinder. This opens up the possibility of arranging a plurality of such hose sections on a transport and pressure roller and pressurizing them individually separately, so that different contact pressures and different circumferential speeds can be achieved even when using only a single, continuous or sectioned transport and pressure roller . Thus, the invention can also be applied to individual transport and pressure rollers which can be of any length. According to the invention, it is thus possible to align veneers with relatively short adhesive areas and to position them precisely.

According to the invention, the pressure fluid is preferably supplied through the shaft, it being possible for the shaft to have at least one central recess for the passage of the pressure fluid, which is connected to at least one radial recess of the shaft, which is in the space between the each hose section and the shaft opens.

The device according to the invention thus allows the longitudinal edges of the individual veneers or veneer sheets to be glued to be aligned exactly with one another, in particular in a line transverse to the transport direction, this being possible both in the case of straight-line and also in the case of corrugated or serrated connecting areas of veneers. So you can According to the invention, veneer sheets with uniform or beveled cut edges can also be positioned precisely and securely and connected to one another.

Fig. 1

eine Teil-Seitenschnittansicht des Arbeitsbereichs einer erfindungsgemäßen Vorrichtung zum Zusammensetzen von Furnieren,

Fig. 2

einen Längsschnitt durch eine erfindungsgemäße Transport- und Anpreßrolle und eine Seitenansicht einer Gegendruckrolle,

Fig. 3

eine perspektivische Ansicht (Explosionsdarstellung) eines Stützzylinders mit Druckplatten,

Fig. 4

einen Teil-Längsschnitt durch eine erfindungsgemäße Transport- und Anpreßrolle gem. Fig. 2 in vergrößerter Darstellung,

Fig. 5

einen Querschnitt durch dieselbe Transport- und Anpreßrolle gem. Fig. 4 entsprechend Schnittlinie III-III,

Fig. 6

eine perspektivische Ansicht eines Teiles der Transport- und Anpreßrolle mit Teilschnitt durch die innere Antriebseinrichtung mit Stützzylinder, Schlauch und Druckplatte gemäß Fig. 3 und Welle.

The invention is described below using an exemplary embodiment in conjunction with the drawing.
It shows:

Fig. 1

2 shows a partial side sectional view of the working area of a device for assembling veneers,

Fig. 2

2 shows a longitudinal section through a transport and pressure roller according to the invention and a side view of a counter pressure roller,

Fig. 3

a perspective view (exploded view) of a support cylinder with pressure plates,

Fig. 4

a partial longitudinal section through a transport and pressure roller according to the invention. 2 in an enlarged view,

Fig. 5

a cross section through the same transport and pressure roller acc. 4 according to section line III-III,

Fig. 6

a perspective view of part of the transport and pressure roller with partial section through the inner drive device with support cylinder, hose and pressure plate according to FIG. 3 and shaft.

A device according to the invention has, in addition to the usual devices, which are known, for example, from a device according to DE-OS 26 14 216, to which reference is hereby made, a stationary table (23) and an upper pressure stamp (24). On the inlet side A, a counter-pressure roller (12) is mounted in / on the upper pressure stamp (24) and a transport and pressure roller (11) in the lower table (23). The pressure stamp (24) can be moved in the vertical direction in order to convey or clamp a veneer introduced in the transport direction A.

In the middle area, the table (23) and the pressure stamp (24) each have a heating device (25, 26), each of which, alone or together, can also be moved relatively vertically, so that they rest in the seam area of the veneers in contact with a veneer sheet (not shown) can be moved to carry out the gluing by means of pressure and heat.

In the outlet area of the table (23) there are furthermore brake stamps (27) which can be actuated via a pressure device (28) in order to hold or brake the incoming veneer.

At the inlet side A of the table (23) ends an inlet conveyor belt (29) on which the veneer strips to be glued are fed. An outlet conveyor belt (30) connects to the outlet side of the table (23) in an analogous manner in order to remove the veneer sheets glued together.

The press roller (12) is mounted on a shaft (31) and connected to it via a toothing or the like. The shaft (31) is connected (in a manner not shown) to a drive, so that, as shown, it can be rotated clockwise.

The transport and pressure roller (11) is mounted on the table (23) and is also driven by a drive, not shown.

The device according to the invention for assembling veneers works in the usual way.

In the left area of the device shown in FIG. 1, a wide glued veneer sheet is held by means of the brake stamp (27), whereby additional stop pins (32), which are mounted on the table (23), can be moved upwards in order to hold the veneer sheet or to position its rear edge exactly. A veneer is then fed via the infeed conveyor belt (29) and the transport and pressure roller (11), which, after the stop elements (32) have been removed from the transport path, is brought into contact with the veneer sheet already present. At the same time, the upper pressure stamp (24) is moved downwards in order to press the incoming veneer and the previous veneer sheets, the previous veneer being firmly clamped in by the brake stamp (27) and the heating devices (25, 26) being pressed lightly on the veneers or the subsequent veneer sheet form a shaft. In this shaft, the following veneer is pressed firmly against the previous veneer sheet by the transport and pressure roller (11) and counter-pressure rollers (12). In addition, the upper and lower heating devices (25, 26) are activated with pressure and heat in order to bond the adhesive applied to the adhesive edge of the new veneer to the other veneer sheet when the new veneer is transported to it. The necessary contact pressure between the veneers is generated and maintained by the transport and pressure roller (11) and the associated counter-pressure roller (12). After a predetermined exposure time, the interconnected veneer sheets are released and transported onward.

In Fig. 2 is a side view of the transport and pressure roller (11) according to the invention and the associated driven counter-pressure roller (12) is shown. The counter-pressure roller (12) is constructed in the usual way, so that a further description is unnecessary.

The transport and pressure roller (11) according to the invention is formed from individual roller sections, each of which has an outer jacket (13) which is designed in the form of a cylinder jacket and consists of a rough material such as hard rubber. This jacket (13) is carried by an inner carrier body (14) made of metal, which is also designed in the form of a cylinder jacket and has a central bore through which a support cylinder (17) with an inner shaft (16) is passed. This shaft (16) is connected in a manner not shown to a lateral drive and has an inner bore (15) through which a pressure medium such as compressed air can be supplied.

The outer circumference of the jacket (13) shows a high coefficient of friction to ensure the transport and pressing of a veneer in a safe manner.

Within each carrier body (14), which forms only a short roller (50 - 100 mm) with the jacket (13), a support cylinder (17) is mounted, which has several parallel elongated recesses (18 ), the end areas of which are rounded and have smooth wall surfaces sloping inwards from the outside.

In each of these recesses (18) there is a curved, removable pressure plate (19), which has an outer covering (20). made of a material such as hard rubber with a high coefficient of friction. This outer coating (20) of the pressure plate (19) rests against the smooth support body (14) of the casing (13) and, with its friction surface, has the task, on the one hand, of taking the casing (13) with it at the same rotational speed or one under slip and contact pressure Allow relative movement, provided that the jacket (13) receives a lower rotational speed due to the fact that a veneer entrained by the jacket (13) encounters resistance (like the edge of a previous veneer sheet).

The frictional force occurring between the outer friction surface of the lining (20) of the pressure plate (19) and the surrounding smooth inner wall of the cylindrical support body (14) is controlled by the elastic wall of a hose (21) which is in sections within all the support cylinders (17) lying next to one another has moved in and is preferably under the pressure of a pressure medium compressed air.

This elastic hose (21), which extends in individual sections over the entire length of the shaft (16) or preferably almost only over the length of a support cylinder (17), consists for example of a plastic and is fully acted upon by a pressure medium on its inside which is guided through a central longitudinal bore (15) in the shaft (16) via the radial transverse channels (22) (cf. Fig. 5) to the hose (21) and has a static effect.

In the area of each recess (18) of the support cylinder (17), the pressure medium presses the flexible hose (21) into this recess (18) in such a way that the narrow, exposed pressure plate (19) moves outwards and with its covering (20) presses against the inner wall of the cylindrical support body (14) and thereby - depending on the Pressure of the pressure medium (e.g. 3 - 6 bar) - there builds up a more or less large friction force.

Since a plurality of recesses (18) are distributed uniformly (at equal intervals) over the circumference of each support cylinder (17), the same friction force is also generated on the inner wall of the carrier body (14) on several surfaces of the same distance.

If a veneer running on the upper apex line of the casing (13) of the transport and pressure roller (11) bumps against a previous veneer sheet (on the left in FIG. 1) and has a curved protruding longitudinal edge, this protruding curved part of the longitudinal edge becomes due the back pressure and thus the relative movement between the jacket (13) and the shaft (16) is not further promoted, while adjacent parts of the longitudinal edge to be glued, which do not yet touch the previous veneer sheet, are transported until the entire longitudinal edge is in line (on the Line of the longitudinal edge of the previous veneer sheet) and can be glued exactly in accordance with the rear longitudinal edge of the previous veneer sheet. For this purpose, the pressure stamp (24) moves downwards and presses the previously correctly positioned longitudinal edges together while heating up the die-gluing adhesive.

Radial grub screws (33) are used for the positive connection between the shaft (16) and the respective support cylinder (17).

Between two transport and pressure rollers (11) each stand on the shaft (16) supported spacer rings (4), which prevent the jacket (13) or the carrier body (14) on the adjacent support cylinders (17) back and forth hikes here which are separately as long as the jacket (13).

As shown in Fig. 2, individual sections of the hose (21) extend almost over the length of each support cylinder (17) and the compressed air spaces are sealed laterally by ring seals (35).

Claims (13)

1. An apparatus for applying veneers

   - having several driven transport and pressure rollers (11) disposed on a drive shaft (16);

   - having at least one counter-pressure roller (12) disposed parallel thereto, by which the veneers are passed through a pressing device (24), whereby the transport and pressure rollers (11) are disposed so that they directly press on the veneer without the addition of chains, belts or similar;

   - having a heating device (25, 26);

   - the transport and pressure rollers (11) also each having a shell (13),

   characterised
   in that between each shell (13) and the drive shaft (16) is disposed a sliding clutch, which connects the shell (13) to the drive shaft (16) in a frictional manner,
   in that the sliding clutch comprises a support cylinder (17) disposed between the inner drive shaft (16) and an inner support member (14) of the shell (13), which cylinder is provided with recesses (18), in each of which a radially movable pressure plate (19) under the pressure of a pressure fluid is disposed, and
   in that on the inside of the support cylinder (17) is fixed an elastic hose (21) to seal the recesses (18), which interacts with the pressure plates (19) under the action of the pressure fluid.
2. An apparatus according to Claim 1,
   characterised in that the shell (13) of the transport and pressure roller is equipped with an outer, harder layer of material having a certain coefficient of friction, which is supported on an inner, cylindrical support member (14) made of metal or similar fixed thereto.
3. An apparatus according to one of Claims 1 or 2,
   characterised in that the shell (13) with the support member (14) is mounted in a freely rotatable manner on the inner support cylinder (17).
4. An apparatus according to one of Claims 1 to 3,
   characterised in that the pressure plate (19) is constructed so that it is outwardly curved.
5. An apparatus according to one of Claims 1 to 4,
   characterised in that the pressure plate (19) comprises an outer friction layer (20) and an inner support layer.
6. An apparatus according to one of Claims 1 to 5,
   characterised in that the drive shaft (16) is equipped with a central longitudinal bore (15) and radial supply bores (22) branching therefrom, which open in a space between the surface of the drive shaft (16) and the elastic hose (21).
7. An apparatus according to one of Claims 1 to 6,
   characterised in that the spaces between the sections of the hose (21) opposite the surface of the drive shaft (16) are sealed from one another laterally so that they are tight to pressure fluid.
8. An apparatus according to one of Claims 1 to 7,
   characterised in that the transport and pressure roller is formed from several individual rollers disposed next to one another, which are retained separately from one another by means of spacer rings (24) supported on the drive shaft (16).
9. An apparatus according to one of Claims 1 to 8,
   characterised in that each portion of the hose (21) extends over the central region of a roller portion.
10. An apparatus according to one of Claim 1 to 9,
    characterised in that on the periphery of the support cylinder (17) are disposed several parallel longitudinal recesses (18) equidistantly from one another.
11. An apparatus according to one of Claims 1 to 10,
    characterised in that the longitudinal recesses (18) of the support cylinder (17) are equipped with outwardly opening, inclined wall faces.
12. An apparatus according to one of Claims 1 to 11,
    characterised in that the pressure plates (19) are equipped with lateral wall faces having the same inclination as the wall faces of the longitudinal recesses (18).
13. An apparatus according to one of Claims 1 to 12,
    characterised in that each removable pressure plate (19) comprises an outer covering as the friction layer (20) made from a material such as hard rubber having a high coefficient of friction.

Images