GB2129367A

GB2129367A - Vertical band sawing machine

Info

Publication number: GB2129367A
Application number: GB08326043A
Authority: GB
Inventors: Paul Stolzer
Original assignee: Keuro Maschinenbau GmbH and Co KG
Current assignee: Keuro Maschinenbau GmbH and Co KG
Priority date: 1982-10-13
Filing date: 1983-09-29
Publication date: 1984-05-16
Also published as: JPS59115116A; IT8348804A0; FR2534508A1; GB8326043D0; IT1168623B

Abstract

In a vertical band saw, a saw band (13) runs over the wheels (10, 11) of a wheel carrier (3). The wheels (10, 11) are at an angle of less than 90 DEG in relation to the cutting plane (4) and the wheel carrier is displaceable on the machine stand in a direction perpendicular to the plane of the paper (Fig. 1) by means of two guides (5, 8) arranged in their direction of action on both sides beside the cutting plane (4). The wheel carrier (3) is pivotable in relation to the workpiece in the plane of the cutting direction. <IMAGE>

Description

SPECIFICATION Vertical band sawing machine The invention relates to a vertical band sawing machine of the type having a machine stand to receive the workpiece in a cutting station on a work table of the machine stand by means of clamping means arranged on both sides of the cutting plane. A substantially vertically-extending wheel carrier is also provided having wheels, which are arranged above and below the workpiece region and one of which is driven; the endless saw band circulates over these wheels.

The saw band runs, for directional stabilisation, through sliding guides arranged above and below the workpiece region and connected with the wheel carrier. The wheel carrier, for moving the band saw in the cutting direction, is guidedly displaceable horizontally on the machine stand transversely of the feed direction of the material to be sawn at the level of the material. The clamping means consist, on the side of the wheel carrier, of a stationary abutment face having a passage opening for the saw band and on the opposite workpiece side of openable and closable clamping jaws.

In known vertical band saws of this kind, the wheel carrier is displaceable in the cutting direction on a central guide about which it is at the same time pivotable for the production of mitre cuts. This results in a relative instability of the guidance of the wheel carrier, which prohibits high cutting outputs and the stresses involved therewith.

Furthermore, in the cutting region, the saw band is twisted through 900 into the plane of the cutting direction out of the plane of circulation, which lies transversely of the cutting plane, in order to make the cut. This requires a correspondingly dimensioned distance between the wheels so that on either side of the cutting region there is sufficient distance-to carry out the twisting of the saw band through 900 without difficulty. This results in a considerable overall size of the known vertical band saw, with the consequent expense.

Moreover, on account of the necessary major twisting of the saw band, the saw band should be as narrow as possible in the working direction, so that the twisting is possible at all in the desired manner. This, however, results in a greatly reduced flexural rigidity of the saw band in the working direction and accordingly there is a danger of flexure of the saw band under the cutting pressure - increased alternating bending stressing - and a reduced cutting performance because the feed force must be adjusted in proportion to the saw band cross-section, which, because of the small width of the band, is kept correspondingly small.

It is the problem of the invention further to develop a vertical band sawing machine of the kind initially described in such a way that, for the same performance, it is of smaller construction in relation to the maximum workpiece cross-section, the cutting performance is increased by more favourable guidance and/or adjustment of the saw band, and at the same time a guidance and retention of the wheel carrier are achieved that are adequate for this increased cutting performance, and they also permit the oblique placing of the wheel carrier with respect to the cutting plane.

Finally in this connection, the clamping of a workpiece by the clamping means is to be stabilised and made independent as regards different directions of forces applied to the workpiece.

On the basis of a vertical band sawing machine of the kind as initially stated, this problem is solved in accordance with the invention by using one or more of the following three features: that the wheels are rotatably mounted on the wheel carrier at an inclination, in relation to the cutting plane, of less than 900, that the saw band is so mounted on sliding guides that it can pivot in the cutting plane, and that the wheel carrier is displaceable on the machine stand by means of two guides arranged, in their direction of action, with a guide on each side of the cutting plane.

Due to this arrangement of the wheels on the wheel carrier in accordance with the invention, it is possible to support the wheel carrier by means of two guides lying in their direction of action with a guide on each side of the cutting plane, which leads to a considerable stabilisation of the wheel carrier and thus to an increase in the smoothness of running of the saw band. Moreover in this way the cutting output can be substantially increased, since now the wheel carrier can take up considerably higher reaction forces without tilting.

Furthermore the twisting of the saw band for the cut by an amount less than 900 permits a shorter distance between the wheels and a greater saw band width in the cutting direction, whereby the machine is of smaller construction as a whole and by means of the mentioned saw band width renders possible a higher cutting output with simultaneous reduction of the danger of the saw band yielding rearwards in the cutting region under the cutting pressure and thus being subjected to a correspondingly heavy alternating bending stressing.

It has proved expedient that the angle lies in the range of 35 to 50 , preferably at 400.

The vertical band saw according to the invention is furthermore distinguished in that the saw band, at the commencement of cutting the workpiece, is guided transversely of the feed direction of the workpiece to be cut between the adjacent wall parts of the passage opening of the stationary abutment face, and that one wall part at the start of the cutting operation is so situated that it resiliently presses on the saw band. Thus specifically for the cutting commencement operation, the saw blade is stabilised in a special manner, so that the cutting commencement can be carried out with cutting power that is considerably increased in comparison with the prior art, without any danger of wandering of the saw bands.

It is expedient if the wall parts have an aperture for the teeth of the saw band on the side facing the workpiece. This opens up the possibility of retracting the saw band only into the region of the said wall parts, which is just outside the workpiece cross-section region, so that special feed movements for the next saw cut are eliminated and in this respect there is some space saving as regards the wheel carrier and its range of movement.

For the return stroke of the saw band after the cut is completed the wall parts can be made greatly displaceable from one another so that collisions between saw band and wall parts do not occur here. By way of example however the possibility also exists that the aperture narrows conically in the direction of the passage opening, so that the saw band can run into the aperture in the return stroke.

A particular advantage according to the invention can arise if the saw band guide secured to the work table can be guided in the feed direction of the saw band between faces of the work table. In this manner the saw band guide has an additional stabilisation transversely of the feed direction of the saw band and in this way an additional smoothness of running of the saw band is rendered possible.

It has further proved advantageous that the wheel carrier, as regards its parts co-operating with the sliding guides, is secured for pivoting in the cutting plane in the direction towards the workpiece. This provides the possibility of an oblique placing of the wheel carrier and thus of the saw band for the sawing of shaped sections, especially of rectangular tubes and beams, since here the resulting maximum saw band engagement length is substantially shorter than with an uninclined saw band. Moreover due to the arrangement for the oblique placing of the wheel carrier, in comparison with horizontal band saws, no substantial change of loading occurs by the oblique placing of the wheel carrier which is effected for a more favourable development of the cutting situation. More particularly, no weightcompensating members are necessary for such an oblique setting.

It has also proved expedient for the stationary abutment faces of the clamping means and the associated stationary parts in each case of the openable and closable clamping jaws to be formed as a frame embracing the maximum workpiece cross-section and possibly the workpiece table, and upper and lower frame members can be arranged horizontally. The clamping jaws can also be guided against movement vertically and transversely of the direction of opening and closing on the upper frame member and against movement vertically on the lower frame member, while guidance against lateral movement can be achieved by strips connecting the upper and lower frame members engaging lateral projections of the clamping jaw bodies.

This results in an especially torsionally rigid construction for the workpiece clamping system, which inter alia contributes to the fact that material in rod form which is advanced from cut to cut cannot ride up between the clamping jaws.

A further advantage of the above-stated construction results from the fact that the upper saw band guide may be guided between the upper frame members in the direction of feed of the saw band. Thus here, just as already said above for the lower saw band guide, there is an additional lateral support for the saw band guide which contributes to further freedom from oscillation and thus smoothness of running in sawing operation.

Finally the saw band guides can be additionally guided in the vertical direction in relation to the work table and the frame members of the clamping means and articulated pivotably to the wheel carrier. This measure serves quite generally for freedom from constraints of the movement of saw band guides in relation to the machine frame and the clamping means. Moreover the necessary mobility also results however when, as provided in the machine according to the invention, the wheel carrier is made pivotable in relation to the machine frame.

Further features and details of the invention appear from the following description of the subject of the invention, which is given by way of example only, with reference to the drawing, wherein: Figure 1 shows the vertical band saw in front view along the section line I-I in Figure 3; Figure 2 shows the vertical band saw according to Figure 1 in side view along the section line Il-Il in Figure 1; Figure 3 shows the plan view of the vertical band saw according to Figures 1 and 2; Figure 4 shows a partial sectional view along the section line IV-lV in Figure 2, as regards the clamping head; Figure 5 shows the plan view of the representation of the clamping head according to Figure 4;; Figure 6 shows a detail of a horizontal section through the stationary abutment face of the clamping means in the region of the passage opening for the saw band, and Figures 7 and 8 show two representations of the cutting direction settings according to Figure 2 with reference to a rectangular tube cross-section.

According to Figures 1 to 3 the vertical band saw according to the invention comprises a machine stand 1 which comprises a workpiece table or work bend 2 on which the workpiece (not shown) is fed to a sawing station.

On the machine frame 1, a wheel carrier 3 is mounted on both sides of the cutting plane 4 for guided displacement of the carrier. By way of example, a circular guide rod serves for this purpose in the guide 5 nearer to the cutting plane, while on the guide more remote from the cutting plane a guide face 6 is provided on which the wheel carrier 3 bears through a support wheel 7.

Above the guide 5 a cylinder-piston unit 8 is arranged, the cylinder of which is secured to the wheel carrier 3, while the piston rod 9 is supported on the machine frame. The cylinderpiston unit serves for the feed of the wheel carrier 3 in the direction towards the workpiece (not shown).

As may be seen from Figures 1 to 3, the wheels 1 0, 11 are inclined in relation to the cutting plane 4 by an angle which is less than 90 , in the present case lying at about 400, in relation to the direction 12 of feed of the material to be worked.

This wheel inclination has the consequence that the saw band 13 twists through an angle correspondingly smaller than 900 between guides 14 and 15, so that the alternating bending stressing of the saw band is considerably reduced.

Due to the fact that the wheel carrier 3 is supported in relation to the machine frame 1 on both sides of the cutting plane 4, an especially stable guidance results which, as especially illustrated in Figure 2, also permits of pivoting the wheel carrier 3 in the cutting plane by means of disengageable connections 15, 1 6 to guide 5, so that oblique cutting starts, especially of sections of box form, are possible, as illustrated in Figures 7 and 8. Figure 7 shows an oblique start of cutting of a box-shaped section 17, whereby the cutting length is reduced in comparison with the vertical cutting commencement length represented by way of example in Figure 8 on the same workpiece 17.

Figures 4 and 5 show, in partial sectional representation, the clamping heads 18 and 19 serving for workpiece retention which, as may be seen especially from Figure 2, are made as structures of frame from which consist of a stationary abutment wall 20, openable and closable clamping jaws 21, machine-fast parts 22 carrying these jaws, and frame members 23, 24 connecting the parts 20 and 22.

Figures 4 and 5 show the clamping heads in individual sectional views, where Figure 4 shows, along the section line IV-IV in Figure 2, that the body 25 of the clamping jaw is guided to and from the abutment wall, but prevented from moving vertically and laterally by means of appropriately shaped profilings on the frame member 23, while it is supported in the vertical direction at 26 on the frame member 24, while lateral guides 27 act against vertical struts 28 which are secured to the upper frame member and lower frame member and extend between these.

It is self-evident that the actuation of the clamping jaws 21 can take place mechanically and/or hydraulically.

With reference to Figures 1 and 2 and with regard to Figure 6, mention should be made of a further object of the present invention. Figure 6 shows the stationary abutment walls 20 of the clamping devices 1 8, 19. Here the saw band 13 is guided between these stationary abutment walls between appropriate hard metal plates 1 4, 1 5, but in such a way that the extreme retracted position of the saw band 13 is between the abutment walls 20 in the manner as illustrated in Figure 6, that is the saw band 13 does not travel back beyond the abutment walls 20, but finds its withdrawn position between these, and an aperture 31 is provided between the abutment wails 20 for accommodating the saw teeth 30.

So that the saw band 13 can be drawn back without collision between the abutment walls 20, the abutment walls can be openable and closable to a slight extent as indicated by the arrows 32.

For the supporting of the saw band 13 at the start of cutting of the workpiece it can also be provided that one of the guide plates 14 or 1 5 is in abutment in sprung form on the saw band 13.

Finally Figure 1 especially shows how the saw band guide 15 can be guided between the clamping heads 18 and 19 or in a corresponding guide aperture of the workpiece table 2, the same also applying to the upper saw band guide 14 in relation to the frame members 23. The guides of the saw band 13 in this way are laterally well fixed and damped against vibrations, so that the power transmittable by the saw band can be increased.

In the case where the wheel carrier 3 is pivotable in the manner as shown in Figure 2, it can be provided that the saw band guides 14 and 15 are likewise pivotably articulated to this wheel carrier, so that in the manner shown in Figure 1 they are horizontally displaceable between the clamping heads 18, 19 or within the machine frame, independently of the oblique position of the wheel carrier 3.

Claims

1. A vertical band sawing machine comprising a machine stand including a work table for receiving a workpiece and retaining it in a cutting station by means of clamping means arranged on both sides of the cutting plane and a substantially vertically extending wheel carrier having wheels which are arranged above and below the cutting station and one of which is driven and over which an endless saw band can circulate and in doing so runs for directional stabilisation through sliding guides arranged above and below the cutting station and connected with the wheel carrier, wherein the wheel carrier, for moving in a cutting direction, is guidedly displaceable horizontally on the machine stand transversely of the feed direction of the material to be sawn at the level of the cutting station, wherein the clamping means has on the side of the wheel carrier a stationary abutment face having a passage opening for the saw band and on the opposite side of the cutting station openable and closable clamping jaws, wherein the wheels are rotatably mounted on the wheel carrier at an angle of less than 900 in relation to the cutting plane, and the saw band is twisted by the sliding guides into the cutting plane, and wherein the wheel carrier is displaceable on the machine stand by means of two guides, one of which is arranged in their direction of action on one side of the cutting plane, and the other guide is arranged on the other side.

2. Vertical band sawing machine according to claim 1, characterised in that the angle lies in the range of 35 to 500, preferably at 400.

3. A vertical band sawing machine according to claim 1 or 2, wherein the arrangement is such that a saw band at the commencement of cutting of the workpiece is guided transversely of the direction of feed between adjacent wall parts of the passage opening of the stationary abutment face and wherein one wall part is resiliently pressable against the saw band at the commencement of cutting.

4. A vertical band sawing machine according to claim 3, wherein the wall parts have an aperture for the teeth of the saw band on the side facing the cutting station.

5. A vertical band sawing machine according to claim 3 or 4, wherein the wall parts are displaceable away from one another for accommodating the saw band on its return stroke at the end of a cutting operation.

6. A vertical band sawing machine according to claim 3 or 4, wherein the aperture tapers in the direction towards the passage opening.

7. A vertical band sawing machine according to any one of claims 1 to 6, wherein the sliding saw band guide located below the cutting station is, in operation, guided, in the feed direction of the saw band, between faces of the work table.

8. A vertical band sawing machine according to any one of claims 1 to 7, wherein the wheel carrier is so secured to the guides that it can pivot in the cutting plane in the direction towards the cutting station.

9. A vertical band sawing machine according to any one of claims 1 to 8, which includes a device for driving the wheel carrier in the cutting plane, wherein the driving device, which is preferably formed as a hydraulically actuated cylinder-piston unit, acts alongside the guide of the wheel carrier nearer to the cutting plane, between its guide part and the machine stand.

10. A vertical band sawing machine according to claim 9 when dependent on claim 8, wherein the pivotability of the wheel carrier on the other guide is constituted by formation of the guide as a wheel mounted rotatably on the wheel carrier and rolling on a track of the machine stand.

11. A vertical band sawing machine according to any one of claims 1 to 10, wherein the stationary abutment faces of the clamping means and the respectively associated stationary parts of the openable and closable clamping jaws are formed as a frame that can embrace the maximum workpiece cross-section and possibly the workpiece table.

12. A vertical band sawing machine according to claim 11, wherein the frame includes upper and lower frame members that are arranged horizontally.

13. A vertical band sawing machine according to claims 11 and 12, wherein the clamping jaws are so guided on the upper frame member that they are prevented from moving vertically and transversely with respect to the direction of opening and closing of the jaws and the jaws are so guided on the lower frame member that they are prevented from moving vertically, and wherein the jaws are further guided against movement transversely of the direction of opening and closing the jaws by lateral projections on the clamping jaw bodies engaging strips connecting upper and lower frame members.

14. A vertical band sawing machine according to any one of claims 11 to 13, wherein the upper saw band guide can be guided between the upper frame members in the direction of feed of the saw band.

15. A vertical band sawing machine according to claims 7, 8 and 14, characterised in that the saw band guides are additionally guidable in the vertical direction in relation to the work table and the frame members of the clamping means, and are pivotably articulated to the wheel carrier.

16. A vertical band sawing machine substantially as hereinbefore described with reference to, and as illustrated in, any one of Figures 1 to 6 of the accompanying drawings.