Feeding system on a woodworking machine

Abstract: The feeding system comprises feed rollers (10, 11, 12, 13, 22, 23, 27, 28) intended for the automatic delivery, advance, and ejection of workpieces. The feed rollers are all driven jointly by a single driving means (6) via various belt or chain drives (5, 31, 39, 41, 42, 44, 45, 47, 48, 50), all have the same peripheral speed and rotate synchronously with an upper cutting head (30) which is driven by the same driving means (6). The feed rollers include delivery rollers (11, 12, 13) disposed before the cutting head and upper (27, 28) and lower (22, 23) ejection rollers disposed after the cutting head. The lower ejection rollers are connected to a vertically adjustable feed table (2). None of the feed rollers need be displaced for adjusting the woodworking machine to different dimensions of workpieces, and the synchronization of the feed rollers and cutting head yields workpieces with uniformly smoothly machined surfaces.

Description: This invention relates to a feeding system on a woodworking machine according to the preamble of claim 1. Woodworking machines of the foregoing type having feeding sytems for delivering, advancing, and/or ejecting workpieces are known. However, the individual feed rollers are often so disposed that it is complicated and time-consuming to reset the machine when processing workpieces of different dimensions, so that the downtime of the machine is substantial. In order to keep this changeover time within reasonable limits, some of the feed rollers of the prior art machines are often not driven, are only optional equipment, or are relatively far from the cutting heads. As a result, machined workpieces are either not automatically ejected or the minimum processing length of a workpiece must be relatively great in order to achieve automatic ejection. It is the object of the present invention to provide an improved feeding system on a woodworking machine of the type mentioned which does not have the above drawbacks. This object is achieved by means of the features recited in the characterizing part of claim 1. Further advantageous embodiments of the feeding system are contained in the features of the dependent claims. The French document FR-A-1 474 470 discloses a machine, in which all feed rollers are driven. Since no vertical cutting heads for machining the side surfaces of the workpiece are provided in the machine, the above problems hardly arise. The particular problem here is that of adjusting the machine to different workpiece machining widths. The British document GB-A-216 471 illustrates a machine with which a workpiece can be machined on three sides. These three surfaces are those which rest on a feed table and the two side surfaces of the workpiece. There are only upper press rollers without a drive to hold the workpiece down on the feed table. Automatic workpiece delivery, advancement and ejection is not possible. The Swiss document CH 398 948 discloses, in accordance with the precharacterising part of claim 1, a stick milling machine for woodworking, in which several operating shafts, disposed in part horizontally and in part vertically, lie one behind the other. Two vertical operating shafts are disposed between two horizontal operating shafts. In front of and behind each machining location there is at least one driven, holding down element for pressing the workpiece on the machining table and for longitudinal conveyance of the workpiece. Each holding down element, which in each case has a holding down roller, is disposed individually on one arm each, containing a gearing. Every arm is disposed pivotably about one horizontal drive shaft, which together are drivable by a motor. All holding down elements, which are disposed in a line, one behind the other, in the machining direction of the workpiece, are adjustable jointly in height and sideways. The machine disclosed is hardly suited to machining relatively wide workpieces, since only an unevenly distributed holding down force can be applied to a wide workpiece due to the relatively narrow holding down elements. The wide workpiece would lie unevenly on the feed table as a result. No lower ejection rollers are foreseen, moreover, in the the machine disclosed here. With the aid of the figures, the feeding system on the woodworking machine according to the invention is described below in detail by way of example. Fig. 1 shows a view of the right-hand side of the machine equipped with the feeding system according to the invention, Fig. 2 shows a side view of the left-hand side of the machine, Fig. 3 shows a partial view of the main parts of the feeding system according to the present invention, and Figure 4 shows a rear view of the machine equipped with the feeding system. As illustrated in Figs. 1 and 2, the machine comprises a frame 1 having disposed thereon a feed table 2 intended as a support surface for workpieces during their delivery, advance, machining, and ejection. The workpieces are fed in the direction indicated by arrow 29. The feed table 2 is secured to slideways 3 for vertical displacement as indicated by arrows 40. Mounted in the machine frame 1 is an electric motor 6 for driving both an upper cutting head 30 and a feeding system comprising feed rollers 10-13, 22, 23, 27, and 28. A first spindle 4, driven via a first chain drive 5, transmits its rotary motion on the left-hand side--viewed from in front of the machine--via a V-belt drive 31 to adjusting means 7, 7′ coupled to the primary shaft of gearing 8 (cf. Fig. 2) for adjusting the peripheral speed of the feed rollers 10, 11, 12, 13, 22, 23, 27, 28. The adjusting means 7, 7′ comprise essentially two frustoconical rollers which are provided with recesses and, axially meshing, are displaceable. The V-belt drive 31 passes between these rollers. The output shaft of the gearing 8 transmits its rotary motion via a second chain drive 39 to the feed rollers 10 and 11. From the feed roller 11 there is a third chain drive 41 for transmitting the rotary motion to a further feed roller 12 from which, by means of a fourth chain drive 42, a feed roller 13 disposed between the feed rollers 11 and 12 is driven. All of the feed rollers 10-13 just mentioned extend over the whole width of the machine. Designating the rollers situated before the upper cutting head 30, in the feed direction 29 of a workpiece, as delivery rollers, and the feed rollers disposed after the said cutting head as ejection rollers, then the feed rollers 11, 12, and 13 are delivery rollers and the feed roller 10 is a first ejection roller. The outside surface of the cylindrical feed rollers may be either corrugated or smooth. In order that even very short workpieces may be automatically delivered and ejected, feed rollers must be disposed immediately before and after the cutting heads. By means of the inventive feeding system, this is admirably accomplished inasmuch as workpieces having a minimum length of only 300 mm can be automatically machined. Because the cover 43 can be swung up, access to the upper cutting head 30 is ensured. As may be seen from Figs. 1 and 3, the feed roller 10 transmits its rotary motion via adjacent intermediate gears 15, 16, for reversing the direction of rotation, to a shaft 14. A fifth chain drive 44, revolving with the shaft 14, drives a gearwheel 19 and a spindle 17. The spindle 17 is the first spindle mounted on the feed table 2 and is vertically adjustable therewith. The gearwheel 19 has a swivel mounting 46 and a compression spring 20 for keeping the chain of the fifth chain drive 44 taut upon vertical adjustment of the feed table 2. By means of a sixth chain drive 45, the spindle 17 further transmits its rotary motion to another spindle 21, from which a seventh chain drive 47 drives the feed rollers 22 and 23. The latter, as lower ejection rollers, are mechanically connected to the vertically adjustable feed table 2. Fig. 4 shows how, on the ejection side of the machine, the feed table 2 is designed as two side tables 32 and 33, one disposed on each side of the longitudinal axis of the machine. Each of the side tables 32, 33 has a vertical cutting head 34, 35 driven by a respective drive motor 36, 37 for machining the lateral surfaces of a workpiece passing between these side tables. The side table 33 is provided for supporting the lower ejection rollers 22, 23 and the spindle 21. The side table 32 is laterally displaceable in the direction indicated by arrow 38 for adjusting the machining width of a workpiece. The ejection roller 23, extending over the entire processing width, is supported for axial displacement in a bore 49 in the laterally displaceable side table 32. Returning to Figs. 1 and 3, it will be seen that via an eighth chain drive 48, the feed roller 10 rotates a driving shaft 25 extending over the entire width of the machine. The shaft 25 is rotatingly mounted at each of its ends in bearing means 54 disposed on the machine frame 1. One or more pressing units 26 are disposed on and slidable along the shaft 25. Each of the pressing units 26 bears two upper ejection rollers 27, 28 disposed in tandem in the feed direction indicated by arrow 29 in Fig. 1. The rollers 27, 28 are connected via a ninth chain drive 50 to a gearwheel 52 driven by the shaft 25. This gearwheel includes a groove engaged by a key 53 disposed on the shaft 25 for transmitting the torque. Further disposed in the pressing units 26 are deviating gearwheels 51 for the necessary deviation of the chain drive 50. Each of the pressing units 26 is pivotable about the shaft 25, firstly in order to exert upon the top of a workpiece being machined the pressure necessary for ejecting it, and secondly in order to ensure good accessibility to the ejection opening when the machine is at a standstill by swinging the pressing units up. Because the units 26 are displaceable along the shaft 25, the active locations of the ejection rollers 27 and 28 can be adapted to the width of a workpiece. In the longitudinal direction of the machine, the ejection rollers are disposed so that the upper and lower ejection feed rollers 27, 28 and 22, 23 are situated substantially opposite one another. The workpiece is thereby held fast between the upper and lower ejection rollers and optimally conveyed by means of the forces acting upon it. All of the aforementioned gearwheels, spindles, and shafts driven by the various belt or chain drives 5, 31, 39, 41, 42, 44, 45, 47, 48, 50 are so dimensioned that the peripheral speed of all the feed rollers 11, 12, 13, 10, 22, 23, 27, 28 is the same. All the feed rollers are driven by the electric motor 6, which at the same time also drives the upper cutting head 30 in the opposite direction from the feed rollers. Synchronization between the speeds of rotation of the feed rollers and of the upper cutting head is thereby achieved. Slowing down of the upper cutting head, e.g., owing to irregularities in the wood being machined, such as knots and the like, brings about a comparable decrease in the speed of the feed rollers. In this way, uniform fineness of the processed surface of the workpiece is obtained. Chain tighteners 24, 24′, and 24″ are provided for adjusting the tension of the various chains. Instead of chain drives, it would also be possible to use belt drives, e.g., toothed belts. In another embodiment, the feeding system might be driven by its own electric motor, which would then not drive the upper cutting head as well. Inasmuch as the lower feed rollers 22, 23 are connected to the vertically adjustable feed table 2 and are mounted only in one side table 33, whereas the other side table 32 is laterally displaceable, the machining dimensions of various workpieces can be adjusted extremely quickly without having to displace feed rollers. Hence the downtime of the machine is correspondingly short. The feeding system is so designed that even workpieces two meters or more in width can be delivered, advanced, and ejected with no problem. Since no feed rollers need be displaced for adjusting the machining dimensions of different workpieces, a machine equipped with the inventive feeding system is suited for computer-controlled setting of the dimensions of the workpieces to be machined.

Claims: A feeding system on a woodworking machine, especially for planing and/or milling workpieces on one or more sides, with a vertically adjustable feed table (2), at least one horizontally disposed cutting head (30) and two vertically disposed cutting heads (34, 35), with cylindrical upper feed rollers (10, 11, 12, 13, 27, 28), all being driven together by a drive means (6) and being intended for the automatic delivery, advance and ejection of workpieces, comprising upper delivery rollers (11, 12, 13) and upper ejection rollers (10, 27, 28), at least one of the delivery rollers (12) in the direction of displacement of the workpiece being disposed in front of the horizontally disposed cutting head (30), the upper ejection rollers (10, 27, 28) are positioned one behind the other in the said direction, one (28) after and at least one (27) in front of the vertically disposed cutter heads (34, 35), wherein two of the upper ejection rollers (27, 28) are pivotable vertically away from the feed table (2), characterized in that on the output side of the machine the feed table (2) is designed as two side tables (32, 33), each comprising one of the vertical disposed cutting heads (34, 35) and at least one of the side tables is displaceable transverse to the longitudinal axis of the machine, wherein there are two of said upper ejection rollers (27, 28) disposed in each of a plurality of pressing units (26), disposed in the region of the side tables (32, 33), all the pressing units (26) are mounted on a single common drive shaft (25) and pivotable vertically away from the side tables (32, 33) around the drive shaft and are distributed along and displaceable on the drive shaft in the longitudinal direction transverse to the longitudinal axis of the machine, wherein the feeding system also comprises lower feed rollers which are lower ejection rollers (22, 23) and which are driven by the drive means (6), wherein the lower ejection rollers (22, 23) are disposed in front of and behind the vertical cutting heads (34, 35), wherein the lower ejection rollers are rotatably mounted in one of the side tables (33) of the feed table (2) and are vertically adjustable with the latter, wherein the lower ejection rollers (22, 23) are disposed opposite the upper ejection rollers (27, 28), and wherein in one of the side tables (32) there is at least one bore running through in which the lower ejection roller (23) disposed after the vertical cutting heads (33, 34) is axially displaceably supported. A feeding system according to claim 1, characterized in that the drive means driving all the feeder rollers (10, 11, 12, 13, 22, 23, 27, 28) is an electromotor (6) which is also intended for driving an upper cutting head (30) in such a manner that the rate of revolutions of the upper cutting head and of the feeder rollers are synchronous to each other. A feeding system according to claim 1 or 2, characterized in that the peripheral speed of all the feeder rollers (10, 11, 12, 13, 22, 23, 27, 28) is the same and in that there are means (7, 7') for adjusting the peripheral speed of the feeder rollers.

Inventors: DE ABREU ALFREDO FERREIRA, DE ABREU, ALFREDO FERREIRA
Applicants: MIDA MAQUINAS IND DO AVE LDA, MIDA - MAQUINAS INDUSTRIAIS DO AVE, LDA.
Application year: 1988
Main classification: B27C1
IPC codes: B27C1, B27B25, B27C5