Improvement in moulding machines for woodworking

Abstract: In an improved through feed moulder, each tool (2, 3, 4, 5) is mounted to a slide (7) and accommodated by a dust hood (8) that also carries the usual two hold-down guides (9, 10), rigidly attached one on either side. A mechanism (13) operating between the hood (8) and the slide (7) is used to match the clearance between the hood (8) and the horizontal bed (1) to a given tool reference diameter (D); the hood (8) is also interconnected with the bed (1) by a measuring device (14) serving to verify the clearance of the entire tool assembly, according to the thickness of the work (6), and displays (15, 16) are used to indicate the tool reference diameter (D) and the distance of the hood (8) from the bed (1).

Description: The present invention relates to an improvement in moulding machines for woodworking. Manufacturers of woodworking machines, and through feed moulders in particular, are known to research continually into the possibilities of enhancing the quality of the machining produced by such equipment and reducing dead time to the minimum obtainable. In the case of through feed moulders, which are designed to machine one or more of the four faces of quadrangular section stock supplied from an infeed line, it has been found that the operations of changing over to different toolage (or size of stock) can be notably lengthy and laborious; the tools utilized, which number at least one for each face of the work but can be more, depending on the type of machining to be executed, are arranged in line along a horizontal bed. The work is fed by wheels (rubber faced, or steel) positioned between the tools and rotating about shafts parallel with the bed, which are supported by and driven together from a back rail in such a way that pieces are directed continuously along the feed path and into engagement with the tools. The four tool heads, designated each to a relative face of the work (taken along the feed direction, right side, left side, top and bottom respectively) are accommodated internally of protective and dust extraction casings and provided with two elements, disposed one on either side and located externally of the casing, by which the work is held down going into, through and beyond the cutting stroke; more exactly, the first hold-down element encountered is angled in order to direct the work onto the tool, whereas the second is positioned parallel to the bed and distanced therefrom at a height that will depend on the prescribed thickness of the machined work. To reiterate, the operation of replacing any one of the tools is lengthy and laborious. In effect, the operator initially must detach the two hold-down elements, separating them from the supporting back rail, before the single tool can be removed; the replacement tool must then be aligned with the bed (according to the new diameter), using handwheels and graduated scales afforded by the machine, by means of which the operator can check and adjust the distance (height) of the axis of rotation of the tool from the bed. This accomplished, the two hold-down elements must be repositioned to suit the diameter of the new tool (the plane occupied by the hold-down elements coincides with the cutting edge at the smallest diameter of the tool), and its distance from the bed (equivalent to the thickness of the work). It will be clear enough from this brief outline that the change procedure for each tool requires a considerable length of time for the operator to accomplish; what is more, the precision with which the replacement tool and the hold-down elements are repositioned is dependent in most instances on the skill and experience of the operator. A further drawback affecting through feed moulders is occasioned by the considerable distance between centres of the feed wheel positioned immediately preceding the horizontal tools, and the first wheel encountered thereafter. This clearly represents a source of difficulty when the work to be machined is of length less than the distance in question, as the workpiece will tend to stand still (for want of driving contact) as soon as it is past the first of the two horizontal tools, remaining unable to reach the wheel next after the second horizontal tool until jogged forward by a further workpiece. This is a defect attributable to the conventional architecture of current machines, in which the distance between centres of the horizontal tools is extremely limited and disallows the interposition even of a single feed wheel, due to the presence of the second hold-down element and to the fact that this is connected directly to the back rail. Accordingly, the object of the present invention is to overcome the drawbacks in question by reordering a moulding machine in such a way that tool change operations can be optimized and rendered still more precise, and the quality of woodworking operations thus further enhanced. The stated object is realized in an improvement as characterized in the appended claims, whereby each of the tools, mounted to a respective positioning slide capable of movement in a direction normal to the work face, is equipped with a hood to which hold-down guides are connected rigidly on either side, and with means operating between the hood and the slide, by which to adjust the distance of the hood from the work face in keeping with a reference diameter assigned to the tool; the hood is also connected rigidly to measurement means, anchored in their turn to a datum coinciding with the work face and serving to measure the intervening distance in keeping with the thickness of the machined work, and carries means by which to display the values of the tool diameter and of the distance separating the hood from the work face. The invention will now be described in detail, by way of example, with the aid of the accompanying drawings, in which: fig 1 is a front elevation showing the arrangement of the tools and the feed wheels in a through feed moulder according to the invention, from which certain parts are omitted better to reveal others; fig 2 is a front elevation of one of the cutting tools in the moulder of fig 1, from which certain parts are omitted better to reveal others; fig 3 shows the tool of fig 2 in plan from above, with certain parts omitted better to reveal others. With reference to the drawings, the improvement in moulding machines for woodworking according to the invention relates to through feed moulders of the type comprising a set of spindle heads installed in-line along a horizontal bed 1 and affording a plurality of tools 2, 3, 4 and 5 (see fig 1) by which the four faces of a workpiece 6 are machined. Considered in relation to the path F followed by the work 6, the four tools are designated right hand vertical, left hand vertical, top horizontal and bottom horizontal respectively, indicating the face of the work 6 machined by the individual tool. Also illustrated in fig 1 are two further tools installed respectively at the start and finish of the moulding cycle, which may contribute to the machining operation according to the format of the work 6; in the case in point, these are a planer 21 (located at the entry end, in relation to the feed direction F) and a universal cutter 22 installed at the exit end and serving to shape angled surfaces. Each tool 2, 3, 4 and 5 is mounted to a respective slide 7 of which the position in relation to the machine will depend on the individual type of tool; these slides 7 (one only is illustrated in fig 1) serve to vary the operating clearance of the tool in the direction normal to a given datum 1 or work face, which happens to coincide with the horizontal bed in the case of the tool 4 shown in fig 1 by way of example. Also associated with each tool 2, 3, 4 and 5, positioned preceding and following in close proximity to each side of the relative tool hood 8, are two hold-down elements 9 and 10 consisting in a pair of guides of which the first 9 encountered by the work 6 is angled in relation to the bed 1 and the second 10 disposed parallel thereto, in such a way as to direct and steady the work, respectively, during the cutting stroke. Fig 1 also illustrates roller means 11 consisting in a plurality of steel or rubber faced wheels 23 positioned at regular intervals along the length of the horizontal bed 1, mounted to a back rail 12 which flanks the bed 1 at the rear, as viewed in the drawings; these wheels 23 provide the means by which the work 6 is fed from one tool to the next. The improvement disclosed consists in providing each tool 2, 3, 4 and 5 with a relative hood 8 and associating the hold-down guides 9 and 10 rigidly with the hood on either side by means of relative screw fasteners 24 and 25. Whilst the improvement is illustrated in conjunction only with the top horizontal tool 4, in the example of the drawings, its extension to any or all of the remaining tools falls clearly within the scope of the invention. The hood 8 is equipped further with adjustment means denoted 13, operating between the hood itself and the slide 7, by which the position of the hood can be varied in relation to the horizontal bed 1 commensurately with a reference diameter D assigned to the tool; this diameter will be determined at each change using the nominal diameter of the tool (preferably the minimum cutting diameter, where the profile is mixed). More in detail, the adjustment means 13 operating between the hood 8 and the slide 7 consist in a lead screw mechanism 17 of conventional embodiment (illustrated schematically in phantom line), and a handwheel 18 mounted to the exterior of the hood 8 giving simple and sure operation; such a mechanism will be connected in turn to respective indication means 15, which in a simple embodiment can take the form of a graduated scale, possibly in conjunction with a display 26 showing the value of the tool reference diameter D. The hood 8 is associated further with measurement means 14, connected in their turn to the datum 1 and serving to verify the clearance afforded by the hood 8 in respect of the thickness of the work 6. In the example illustrated, measurement means 14 consist in a linear potentiometer 19 of which one end 19a is attached to the side of the hood 8, adjacent to the first hold-down guide 9, and the remaining end 19b, or drawbar, is anchored to the bed 1 and slidable internally of the body of the potentiometer 19. The potentiometer 19 (which effects an absolute measurement) will be connected to visual indication means 16 consisting in a display 20 wired to and piloted by the potentiometer circuit. With a structure of this type, the machine operator need do no more, when the need arises to remove one of the tools (whether in changing to another type of moulding or replacing a damaged or worn cutter), than open the protective hood 8, remove the tool in question and fit its replacement, then reposition the hood 8 in such a way as to bring the plane of contact of the hold-down guides into alignment with the lesser diameter of the tool, i.e. such that the value appearing in the display 26 corresponds to the reference diameter D. This done, the distance separating the hold-down elements from the bed 1 will undoubtedly differ from that which existed previously (due to the different diameter D of the replacement tool); the current value, effectively reflecting a new thickness, is indicated directly by the potentiometer display 20. At this juncture, manoeuvring the slide 7 by way of the respective adjustment means, and referring directly to the display 20, the operator can reposition the entire hood/hold-down assembly at the requisite clearance. The expedient thus enables greater despatch in replacing and positioning moulding cutters, and in repositioning the relative hold-down elements, thereby speeding up those procedures which with conventional moulding toolage tend to be lengthy and laborious. In addition, the displays give a notably precise indication of the tool diameter, and more especially of the thickness of the work.

Claims: An improvement in through feed moulding machines for woodworking of the type comprising an assembly of spindle heads positioned in close proximity to a horizontal bed (1) and designed to machine four faces of a workpiece (6) with a plurality of tools (2, 3, 4, 5) each mounted to a respective slide (7) by means of which the position of the cutting edge can be adjusted through a direction normal to the work face, wherein each tool (2, 3, 4, 5) is housed internally of a respective hood (8) preceded and succeeded by hold-down guides (9, 10) serving to direct and steady the work (6) through the cutting stroke, and the work (6) is fed from one tool to the next by roller means (11) occupying the entire length of the horizontal bed (1) and mounted to a rail (12) flanking the bed to the rear, characterized in that the hold-down guides (9, 10) relative to each tool (2, 3, 4, 5) are attached rigidly to the corresponding sides of the respective hood (8), and in that the machine further comprises: means (13) operating between the hood (8) and the tool slide (7), by which the clearance between the hood and the work face is adjustable commensurately with a reference diameter (D) of the tool; means (14) connected to the hood (8) on the one hand, and to a fixed datum on the other, by which to measure the clearance between the hood (8) and the work face in respect of the thickness of the work (6); and means (15, 16) affording visual indication of the value of the diameter (D) of the tool (2, 3, 4, 5) and the value of the clearance between the hood (8) and the work face. An improvement as in claim 1, wherein adjustment means (13) operating between the hood (8) and the slide (7) consist in a lead screw mechanism (17) worked by a handwheel (18) mounted to the external surface of the hood (8) and linked to corresponding visual indication means (15) that consist in a graduated scale. An improvement as in claim 1, wherein measurement means (14) consist in a linear potentiometer (19) made fast by one end to the side of the hood (8) adjacent to the first hold-down guide (9) and at the remaining end to a datum (1) coinciding with the work face, and connected to corresponding visual indication means (16) that consist in a display (20) wired to and piloted electrically by the potentiometer.

Inventors: GEMMANI GIUSEPPE, GEMMANI, GIUSEPPE
Applicants: SCM SPA, SCM S.P.A.
Application year: 1990
Main classification: B27C1
IPC codes: B27C1, B27C5, B23Q3, B27B25, B27G19