EP0607914B1 - Device for feeding workpieces in an automatic woodworking machine tool - Google Patents

Abstract

In the case of a device for feeding workpieces in an automatic woodworking machine, in particular a trimming installation, a clamping arrangement is provided on each clamping carriage. The clamping arrangement consists of two clamping devices which act perpendicularly to a bearing plane or to a stop plane perpendicular thereto. To simplify the putting-down and taking-off of the workpieces, the one clamping device has a clamping support (30) which is arranged sunk in the bearing plane, extends parallel to the bearing plane and is guided to be movable perpendicular to it, whereas the other clamping device comprises a stop (11) which is fixed to the clamping support (30) and a clamping member (12) which is guided longitudinally movably on the clamping support, both of which project beyond the bearing plane, the workpiece which is clamped between the stop (11) and the clamping member (12) being drawn onto the bearing plane by the sinking-in movement of the clamping support (30). Preferably, the clamping member (12) is guided horizontally by means of an endless chain (39) and can be tilted outwards at the free end of the clamping support by deflection of the chain (39). By suitable cooperation of the clamping devices, it is possible to arrange the latter on an arm (7) which is mounted on the clamping carriage to be pivotable about a shaft (8) pointing in the direction of travel.

Description

The invention relates to a device for guiding the workpieces in an automatic woodworking machine, in particular for processing squared timber for construction purposes, according to the preamble of claim 1.

The guide device forms an essential part of a machine system for machining, which is also referred to as a joinery system or woodworking center. Usually, several common movable tensioning carriages are provided, which form a common support level and a common stop level. With the guide device, the workpiece is not only brought into the right place and held for processing, but, depending on the processing, is also moved extremely precisely during this, this movement influencing the processing result. The guide device thus forms one of the five axes of movement of the CNC-controlled system, for example. So it is it is clear that the workpiece must be clamped firmly and with a clear spatial reference to the clamping carriage.

A guide device of the type described in the introduction is known from European patent application 0 267 156. The tensioning carriages each have a vertical stop rail and a horizontal support rail. With the help of a clamping cylinder, the workpiece is pressed against the stop rail and pressed onto the support rail from above by means of a clamping rail. The clamping rail can be folded up using a swivel cylinder to place and remove the workpiece. For the clamping movement, this known clamping rail has a spindle drive or a clamping pad that can be placed under pressure on the contact surface with the workpiece.

Clamping a workpiece on the clamping carriage is therefore relatively cumbersome, because the clamping rail must first be lifted up and the clamping cylinder must be moved on the support rail in accordance with the width of the workpiece. The clamping devices are also built to be relatively wide. The clamping rail interferes with the machining of the workpiece side on which it rests.

The invention has for its object to equip the clamping carriage with clamping devices that make it easier and faster to clamp the workpiece and that together form a compact structural unit.

This object is achieved by the characterizing features of claim 1. Then takes the place of the clamping rail crossing the workpiece a clamping beam, which can also make a clamping movement in the direction perpendicular to the support plane and parallel to itself, but does not cross the workpiece, but below the workpiece in the Support level is sunk. A stop is firmly connected to the tensioning beam and, together with the stops of the other tensioning carriages, defines the stop plane perpendicular to the support plane and lying in the direction of travel. Furthermore, a tensioning element is guided to move longitudinally over the entire length of the tensioning support and cooperates with the stop. The workpiece, for example a beam, can thus be placed freely on the clamping carrier, after which it is pressed against the stop by the clamping element. If the clamping carrier now plunges further into the support plane, the workpiece clamped between the stop and the clamping member is placed in a direction perpendicular to the clamping forces, ie with the aid of the clamping friction forces, placed on the support plane. The same effect is achieved as if the workpiece were pressed firmly onto the support plane in a known manner. Another advantage is the fact that the initial position of the clamping beam before the clamping movement is always the same, ie does not depend on the height or thickness of the workpiece.

Both tensioning processes take place automatically one after the other. The interaction of the clamping devices of a plurality of clamping carriages straightens a beam that is curved or twisted, ie. H. it regains its theoretically correct shape and can therefore also be edited precisely. It should be noted here that the workpiece advantageously does not rub against the stop in the second clamping step, since this moves in the clamping direction. The workpiece is thus fixed more securely and precisely in the clamping position.

The support plane of the individual tensioning carriage is preferably formed by support supports spaced apart in the direction of travel. The tensioning beam is guided between them and immersed in a lifting cylinder that supplies the tensioning force. driven. A suitable sliding guide ensures that the tensioning movement of the tensioning beam is parallel to the support plane and to itself.

In order to further facilitate the placement and clamping of workpieces of different widths, it is proposed that the clamping member be guided along the clamping carrier by means of an endless chain and can be tilted outwards at its free end by deflecting the chain. Normally, the support level and the clamping beam will be placed horizontally, in which case it would be necessary to lift the workpieces over the upward clamping element. This is particularly unfavorable if the workpieces are placed on the forklift. If, on the other hand, the deflection point of the chain at the end of the tensioning bracket is designed so that the tensioning element attached to the chain can be guided around at least a little, it swivels outwards and dips below the support level, so that the loading path is free.

In practice, it is provided that the tensioning member is pivotably mounted with respect to a chain link about an axis perpendicular to the chain plane and is supported on a further chain link on the side opposite the stop by means of an articulated support. The articulated support is preferably designed to be adjustable in length in order to be able to adjust the tensioning element at right angles to the tensioning support. On the other hand, this solution has the advantageous consequence that the rod ends attached to chain links spread out at the deflection point of the chain, the joint arrangement stretches somewhat and thereby swivels the tensioning member faster and further downward.

The chain is expediently driven by a hydraulic motor. Its adjustable maximum torque determines the clamping force.

If the workpiece is to be rotated with respect to its longitudinal axis in order to carry out certain machining operations, it is advantageous if the clamping devices do not have to be released for this. To achieve this, it is proposed that the clamping devices be arranged on an arm which is pivotally mounted on the clamping carriage about an axis pointing in the direction of travel. In the clamping devices described, the support beams form the swivel arm. They are connected to each other and thus form a swivel scaffold in which all other essential components of both clamping devices - clamping bracket, stop, clamping element and the clamping drives - are integrated.

In particular at a swivel angle of 90 °, which is precisely defined by angle stops, the swivel movement can be carried out by means of a lifting cylinder. It is therefore not necessary to loosen the clamping devices, but rather they are pivoted together with the clamped workpiece, so that this reaches a precisely defined pivot position without changing the shape and can be further processed immediately if the machine tool is appropriately programmed. Multiple swiveling back and forth is possible during the entire machining cycle, since there is hardly any loss of time during swiveling.

Fig. 1

einen Vertikalschnitt I-I einer Spannanordnung eines Spannwagens,

Fig. 2

eine Draufsicht der Spannanordnung nach Fig. 1, teilweise horizontal geschnitten,

Fig. 3

einen Querschnitt III-III des Spannarms der Anordnung nach Fig. 1 in größerem Maßstab,

Fig. 4

einen Querschnitt IV-IV der Spannanordnung nach Fig. 1 und

Fig. 5

die Ansicht eines Spannwagens, auf dem eine Spannanordnung gemäß Fig. 1 montiert ist, in Fahrrichtung gesehen.

An embodiment of the invention is explained below with reference to the drawing. In detail shows

Fig. 1

a vertical section II of a tensioning arrangement of a tensioning carriage,

Fig. 2

2 shows a top view of the tensioning arrangement according to FIG. 1, partially horizontally,

Fig. 3

2 shows a cross section III-III of the tensioning arm of the arrangement according to FIG. 1 on a larger scale,

Fig. 4

a cross section IV-IV of the clamping arrangement according to Fig. 1 and

Fig. 5

the view of a wagon on which a tensioning arrangement according to FIG. 1 is mounted, seen in the direction of travel.

First, the essential assemblies of a workpiece guide device are presented with reference to FIG. 5. On several blocks 1 fixed to the building, a box section tube 2 is fastened, to which prism rails 3 are welded on both sides, which represent the guideway. A tensioning carriage 4 runs with a plurality of not shown, prestressed rollers on the prism surfaces, i. H. it moves perpendicular to the plane of the drawing and is driven by a motor 5 or other drive means.

A base frame 6 is attached to the tensioning carriage 4, which essentially consists of two parallel plates. Between these there is a swivel arm 7 which can be swiveled on swivel pins 8 from its horizontal into a vertical position. The swivel arm is provided at the top with two support strips 9 made of hard rubber or a plastic. A wooden beam 10 to be machined lies across this support ledge and is clamped between a stop 11 and the pressure plate 12 of a tensioning element. With the same clamping arrangements, the beam is clamped in total on several clamping carriages. By folding up the swivel arms 7, it is also accessible on the underside for machining tools on the length ranges between the clamping arrangements.

Details of the swivel arm 7 result from the remaining figures. It consists of two parallel plates 13, on the upper edge of which a support flange 14 is folded outwards. The support strips 9 are attached to the support flanges.

It can be seen in particular from FIGS. 2 and 4 that the plates 13 are each fastened to the side faces of a C-profile rail 15, which to a certain extent forms the backbone of the swivel arm 7. Because of the bearing arrangement, the fastened section of the plates 13 does not reach their full height, rather the plates have a rectangular cutout at the upper left corner (FIG. 1). In the area of its lower edge, the plates 13 are connected to one another by a base plate 16.

The base frame 6 has a U-shape in plan view. Two bearing plates 17 form the legs and are connected to one another by a web 18. Furthermore, a fastening plate 19 serves to connect and stiffen the bearing plates 17.

The C-profile rail 15 is mounted in the bearing plates 17 by means of the pivot pin 8. For this purpose, bearing rings 20 are inserted into the bearing plates 17 and, on the other hand, fastening rings 21 and 22 are also welded to the C-profile rail, which hold the bearing pins 8 firmly. Since the space inside the C-profile rail must remain free, a continuous pivot pin is forbidden. For pivot actuation, an eye consisting of two levers 23 is welded to the C-profile rail 15, on which the piston rod 24 of a lifting cylinder 25 engages. The lower end of the lifting cylinder is fastened to the downward-reaching part of the base frame 6 by means of a cross bolt 26. In order to be able to set the swivel angle precisely, there is a stop screw 27 on one of the levers 23, which interacts with a stop 28 on the web 18. The horizontal position of the swivel arm can be adjusted by means of an adjustable stop 29 attached to the fastening plate 19.

In the structure described so far, the clamping devices are still missing. These are by a clamping bracket 30 realized or attached to this. The tensioning support 30 can move up and down in the swivel arm 7 according to FIG. 1 in the direction of the arrow. The cross-section of the tensioning beam is shown, inter alia, in FIG. 3. It consists of two U-profile sheets 31 and 32, which are fastened to one another with their web surfaces. The U-profile 31, which is open at the top, consists of a stronger sheet metal. It is responsible for the supporting function. It is screwed to a slide 34 by means of an end flange 33. The U-profile plate 32, the outline of which results from FIG. 1, has bevelled edges on the left end face and is also fastened to the slide 34 with these. The slide has grooves on the side. The folded edge strips of the C-profile rail 15 engage in this, which thus serves as a guide for the slide 34. At the upper end cut off according to FIG. 2, the slide has a protrusion 35 protruding at a right angle. The piston rod 36 of a lifting cylinder 37, which is located in the C-profile rail 15 and the lower end of which by means of a cross bolt 38 at the lower end, is fastened to this the C-profile rail 15 is mounted. Thus, by means of the lifting cylinder 37, the tensioning support 30 can be moved parallel to itself and to the support strips 9, namely up and down according to FIG. 1.

A double chain 39 is guided in the tensioning support 30. The upper section between a deflection roller 40 and a deflection piece 41 made of plastic runs in the U-profile plate 31. After the deflection roller 40, the chain is guided downward, placed around a sprocket 42 and returned to the deflection piece 41 via a tensioning piece 43. This lower chain section runs in the U-profile plate 32. The sprocket 42 sits on the shaft of a hydraulic motor 44. This is fixed to the U-profile plate 32, as are the other deflection parts 40, 41 and 43 between the legs of the U- Profile sheet 32 are stored or held.

What is essential is the form-fitting guidance of the upper section of the double chain 39, which can be seen in FIG 39 Close tightly around the top, bottom and sides. In this section, two joint pieces 47 are fastened to the double chain 39 at a short distance. Your narrow tongue 48 is inserted between two successive coaxial chain links and penetrated by the two common chain pins. With their flat part adjoining the tongue, the joint pieces slide on the flat upper surface of the sheet metal profiles 45. Thus, if forces act on the chain upwards or downwards via the tongues 48, it can withstand this as a result of the support described.

On one of the hinge pieces 47, a pressure piece 49 is mounted, which carries the pressure plate 12 already mentioned and is supported on the other hinge piece 47 via a length-adjustable articulated support 50. This can be clearly seen in FIG. 1. This tensioning element attached to the double chain 39 with its pressure plate 12 interacts with the stop 11 which, like the entire tensioning support 30, is fastened to the slide 34. If there is a workpiece between the pressure plate and the stop, the hydraulic motor 42 stops while maintaining its set maximum torque. 1 is activated in the horizontal direction.

The second tensioning device is activated by actuating the lifting cylinder 37 in the sense of a retracting movement of its piston rod 36. The entire tensioning support 30 is thereby moved downward in the direction of its sliding guide. This is possible because not only the sheet metal profiles 31 and 32 can move between the plates 13 of the swivel arm, but also the stop 11, the pressure plate 12 and the other parts of the tensioning element with regard to their width extent fit into the gap formed by the support strips 9. Even in the initial position of the tensioning support according to FIGS. 1 and 3, the stop 11 and the pressure plate 12 already engage between the support strips 9. Due to the displacement of the tensioning support, referred to above as the sinking movement, tensile forces are exerted downward on the clamping elements adhering to the workpiece and pull the workpiece firmly onto the support strips 9. In the normal case, when the workpiece rests on the support strips 9 at the start of the clamping movement, the clamping stroke is extremely small. Otherwise, when e.g. B. a longer bar is not due to its curvature on the relevant support strips 9, it is pulled down to the support and thereby aligned.

When pivoting the entire swivel arm 7, as described in relation to FIG. 5, both the support strips and all of the tensioning elements installed in the swivel arm also pivot. If the hydraulic motor 44 protrudes laterally beyond one of the bearing plates 17 due to its design, a corresponding recess must be provided on the latter, so that the pivoting process is not hindered. The operation of the clamping elements is independent of the swiveling process. So you can swivel in the cocking position. If several clamping arrangements of different clamping carriages attack on a beam, all swivel arms swivel at the same time. Since the stop plane, i.e. H. the surface of the stops 11, and the support plane, d. H. the surface of the support bar 9, in the pivoted position are again precisely defined, the initial values for machining are also fixed in the pivoting position.

A main advantage of the invention is that the workpieces can be placed on the support strips 9, without having to swivel away a terminal strip crossing above.

1

Bock

2

Kastenprofilrohr

3

Prismenschiene

4

Spannwagen

5

Motor

6

Basisgestell

7

Schwenkarm

8

Schwenkzapfen

9

Auflageleiste

10

Holzbalken

11

Anschlag

12

Druckplatte

13

Platte

14

Tragflansch

15

C-Profil-Schiene

16

Bodenblech

17

Lagerplatte

18

Steg

19

Befestigungsplatte

20

Lagerring

21

Befestigungsring

22

Befestigungsring

23

Hebel

24

Kolbenstange

25

Hubzylinder

26

Querbolzen

27

Anschlagschraube

28

Anschlag

29

Anschlag

30

Spannträger

31

U-Profil-Blech

32

U-Profil-Blech

33

Flansch

34

Schieber

35

Vorsprung

36

Kolbenstange

37

Hubzylinder

38

Querbolzen

39

Doppelkette

40

Umlenkrolle

41

Umlenkstück

42

Kettenrad

43

Spannstück

44

Hydromotor

45

Blechprofil

46

Kunststoffprofilleiste

47

Gelenkstück

48

Zunge

49

Druckstück

50

Stütze

A further simplification of the loading process is achieved by folding away the pressure plate 12 shown in FIG. 1. Dashed lines indicate how the tensioning element initially moves in a straight line to the right until the leading joint piece 47 reaches the deflection piece 41. From then on, the two joint pieces 47 begin to spread, which has the consequence that soon after the trailing joint piece has begun to incline, the pressure piece 49 tilts over and plunges below the support plane. Thus, even when loading and unloading the tensioning carts quickly, there is no danger that the uncontrolled movements of the often heavy workpieces will trigger the upstanding clamping elements and thereby damage the clamping device. Rather, the workpieces can simply be pushed over the support strips 9. However, the hydraulic motor 42 is to be programmed in such a way that it brings the tensioning element into the end position shown in broken lines with each opening movement.

1

Buck

2nd

Box section tube

3rd

Prism rail

4th

Tension wagon

5

engine

6

Base frame

7

Swivel arm

8th

Trunnion

9

Support bar

10th

Wooden beams

11

attack

12th

printing plate

13

plate

14

Supporting flange

15

C-profile rail

16

Floor panel

17th

Bearing plate

18th

web

19th

Mounting plate

20th

Bearing ring

21

Mounting ring

22

Mounting ring

23

lever

24th

Piston rod

25th

Lifting cylinder

26

Cross bolt

27

Stop screw

28

attack

29

attack

30th

Clamping beam

31

U-profile sheet

32

U-profile sheet

33

flange

34

Slider

35

head Start

36

Piston rod

37

Lifting cylinder

38

Cross bolt

39

Double chain

40

Pulley

41

Deflector

42

Sprocket

43

Clamping piece

44

Hydraulic motor

45

Sheet profile

46

Plastic profile strip

47

Joint piece

48

tongue

49

Pressure piece

50

support

Claims (5)

1. Device for feeding workpieces in an automatic woodworking machine tool, in particular for working squared timber for building purposes, with at least one carriage moving on a linear guideway, which carriage forms a bearing plane and a stop plane perpendicular thereto and comprises separate clamping devices acting perpendicular to these planes in order to clamp a workpiece to the carriage, characterised in that one clamping device comprises a carrier (30) arranged sunken in the bearing plane, which extends parallel relative to the bearing plane and is guided moving perpendicular thereto (15, 34), and in that the other clamping device comprises a stop (11) secured to the carrier (30) and a clamping element (12, 49, 50) guided moving in longitudinal direction on the carrier, both of which project over the bearing plane, whereby the workpiece clamped between the stop (11) and the clamping element (12) is drawn by the sinking movement of the carrier (30) to the bearing plane.
2. Device according to claim 1, characterised in that the bearing plane is formed by two bearing carriers (9) spaced apart in the travelling direction of the carriage (4) and the carrier (30) is guided dipping between the latter and is driven by a lift cylinder (37).
3. Device according to claim 1, characterised in that the clamping element (12, 49, 50) is guided by means of an endless chain (39) along the carrier (30) and is tiltable at its free end by the outwards turning of the chain.
4. Device according to claim 3, characterised in that the clamping element (12, 49) is pivot mounted relative to a chain element about an axis perpendicular to the chain plane and is supported by means of a link support (50) on a further chain element.
5. Device according to claim 1, characterised in that the clamping devices are arranged on an arm (7) which is pivot mounted on the carriage (4) about an axis (8) pointing in the travelling direction.

Images