GB2290496A

GB2290496A - Positioning device for blades on cutting machines

Info

Publication number: GB2290496A
Application number: GB9512694A
Authority: GB
Inventors: Rudolf Supe-Dienes
Original assignee: Dienes Werke fuer Maschinenteile GmbH and Co KG
Current assignee: Dienes Werke fuer Maschinenteile GmbH and Co KG
Priority date: 1994-06-22
Filing date: 1995-06-22
Publication date: 1996-01-03
Anticipated expiration: 2015-06-22
Also published as: GB9512694D0; DE9410069U1; IT1276766B1; ITMI951337A1; GB2290496B; ITMI951337A0; DE29509893U1

Abstract

A device for the positioning of lower blades on length-wise cutting machines comprises a blade 11 mounted on a blade shaft 10. A carriage 14 is mounted on a linear guide 21 for displacement parallel to shaft 10. Gripping members compdsing tongs 15 extend from the carriage and their inner surfaces 16 are made to contact outer peripheral surfaces 13 of the blade. Sensors 17, 18 mounted on the carriage detect the position of the cutting edges (12 Fig 2) and, via a controller, set the distance between cutting edges of the blades. The sensors may take the form of optical lasers. <IMAGE>

Description

POSITIONING DEVICE FOR LOWER BLADES ON STRAIGHT-LINE CUTTING MACHINES The invention relates to a device for the positioning of lower blades on straight-line cutting machines, wherein the lower blades are displaceably mounted on a lower blade shaft, are single- or multi-cut and are of bush-type construction, and wherein the positioning device comprises a carriage, which can be displaced on a linear guide aligned at a distance parallel with the lower blade shaft by means of a displacement device to be connected to the bush-type lower blade, and a controller for setting the distance between the cutting edges of the lower blades.

A positioning device with the aforementioned features has become known through use; such a positioning device is of particular importance with a lower blade of bush-type construction with one or more cutting edges because for the re-grinding of the cutting edge all of the bush-type lower blades have to be removed individually from the lower blade shaft bearing the latter and positioned again with setting of the width of cut after the grinding. Lower blades with several cutting edges are known as so-called "multi-grooved knife blocks", while lower blades with only one cutting edge are known as "bottom knives".For the positioning the bush-type lower blades known in this context are provided with a peripheral groove, with which a carriage-mounted displacement device, for example in the form of a movable arm, engages in a form closure, so that with the movement of the carriage the bush-type lower blades connected in a form closure can also be displaced by means of the lower blade shaft and brought into the correct position. The known device also comprises a controller for displacement of the carriage and hence of the bush-type lower blade connected thereto in accordance with reference marks impervious to mechanical influences.

The known positioning device is subject to the disadvantage first of all that the work required for producing the groove in the bush-type lower blade is particularly demanding; both this groove and the displacement device have in fact to be adjusted to one another with high accuracy of fit, so that the cutting edge provided on the bush-type lower blade can also be positioned with the required accuracy. Since the groove can be cut only near to the cutting edge in the bush-type lower blade, the bushtype lower blade has to have a minimum width, whereby a minimum width of cut between individual cutting edges of different bush-type lower blades cannot be fallen short of.

A further disadvantage consists in the fact that because of the re-grinding of the cutting edge the distance between the cutting edge requiring exact positioning and the groove as a point of application for the displacement of the bushtype lower blade is modified by the degree of re-grinding of the cutting edge, so that this dimensional modification has to be loaded into the controller as a correction factor for setting the width of cut. This leads to the further disadvantage, however, that either all the bush-type lower blades or cutting edges have to be re-ground to the same extent or that an individual correction factor has to be determined in a demanding manner for each bush-type lower blade and loaded into the controller.

The object of the invention is therefore to improve a positioning device with the features according to the preamble in such a way that the work-load for the production of the bush-type lower blades is reduced and their positioning is simplified.

The achievement of this object follows, together with advantageous developments and refinements of the invention, from the content of the claims which are attached to this description.

The invention provides in detail that the displacement device is constructed as a gripping device impinging on the bush-type lower blade and that there is disposed on the carriage bearing the gripping device an optical laser or sensor for detecting the position of the cutting edges.

The invention possesses the advantage that because of the direct impinging of the gripping device according to the invention on the bush-type lower blade any additional production work on a form closure arrangement which would otherwise be required on the lower blade is avoided. Nor are any reference lines produced which require the introduction of a correction factor for the displacement of the bush-type lower blade for the renewed setting of the width of cut after a blade re-grinding. The provision of at least one optical laser or sensor on the carriage travelling above the lower blade shaft makes it possible to determine objectively and directly the position of the cutting edges and hence also to undertake a direct guiding of the bush-type lower blades into the predetermined width of cut position of the cutting edges.

There is admittedly already known from DE 41 06 069 C1 a positioning device in which the position of the cutting edges of blade holders is determined by a passing optical sensor and thereafter a correction of the blade holder in terms of the width of cut is carried out according to the degree of re-grinding determined by the optical sensor.

This device refers however to individual blade holders displaceable separately on their own, with which regrinding of the individual blades and subsequent correction of the position of the blade holder is also possible without raising of the cutting width setting, and furthermore a positive interlocking and unlocking of the individual blade holders is also provided in this known positioning device either with an associated support beam or with a separate transport rod: this known solution is not applicable to lower blades accommodated in the form of a bush-type construction arranged on a lower blade shaft.

One embodiment of the invention provides that the gripping device is constructed as a pair of tongs with two tong members which impinge on the front ends of the bush-type lower blade.

An alternative embodiment of the invention provides that the gripping device impinges non-positively on the smooth outer peripheral surface of the bush-type lower blade and is constructed as a pair of tongs with two tong members which embrace the bush-type lower blade. Moreover the tong members can display on their inner sides resting against the bush-type lower blade a frictional configuration; this frictional configuration can consist for example of a lining possessing a suitable coefficient of friction or of a suitable configuration of the surface of the inside of the tong members, for example in the form of a fluting.

Alternatively it is possible in the same manner to provide the outer peripheral surface of the bush-type lower blade with a suitable frictional configuration in the area where impingement of the tong members is involved.

A further embodiment of the invention provides that the tong members are provided on their inner sides coming to rest against the outer peripheral surface of the bush-type lower blade with at least one ball bearing whose ball engages with a groove formed in the outer peripheral surface of the bush-type lower blade. This presents the advantage that a positional correction of the respective bush-type lower blade can also take place when the blade shaft is already rotating, because in this case the still rotating lower blade can run past the ball bearings disposed on the inside of the tong members; since the ball bearings concerned engage with a groove disposed on the outer periphery, axial displacement of the lower blade by means of the lower blade shaft is possible.An arrangement of this kind is advantageous if the bush-type lower blades are fixed to the blade shaft for example by an expansion device.

A particular embodiment of the invention provides that two optical lasers are disposed on the carriage in such a way that the laser beams emitted by them are in the area of the blade bushes to be scanned spaced a small distance apart which can also be variably adjustable; this measure makes it possible to determine unequivocally the position of the cutting edges, which is not particularly clear form-wise in the case of a bush-type lower blade.

In the drawings are reproduced embodiments of the invention, which are described below.

Fig. 1 shows the lower blade shaft with a lower blade constructed after the manner of a bush and a gripping device in a diagrammatic representation in side view, Fig. 2 the subject-matter of Figure 1 in a partial front view, Fig. 3 the subject-matter of Figure 1 in another form of embodiment, Fig. 4 a further form of embodiment of the subject matter of Figure 1, and Fig. 5 another form of embodiment of the gripping device impinging on a lower blade.

On a lower blade shaft 10 are disposed a plurality of bushtype lower blades 11 which are displaceable or alternatively stoppable in a designated position, of which only one bush-type lower blade 11 is shown in the figures.

As can be seen in detail in Figure 2, a cutting edge 12 is ground in known manner into the bush-type lower blade 11 with the formation of a cutter groove 19, while the bushtype lower blade 11 otherwise possesses a smooth outer peripheral surface 13. On a linear guide 21 aligned parallel with the lower blade shaft 10 is disposed in a displaceable manner a carriage 14, on which two tong members 15 are movably disposed in such a way that the tong members 15 can be brought to rest by sections of their inner sides 16 against the smooth outer peripheral surface 13 of the associated bush-type lower blade 11, as follows from Figure 1, in which the tong members 15 have assumed their displacement position for the bush-type lower blades 11.

As shown by way of example in Figure 3, the inner sides 16 of the tong members 15 can be provided alternatively or in addition to the outer peripheral surface 13 of the bushtype lower blades 11 with suitable frictional configurations 22, for example in the form of a friction lining or a fluting.

It follows from Figure 4 that the inner sides 16 of the tong members 15 can also comprise at least one ball bearing 23, wherein in the embodiment shown two ball bearings 23 are shown for a tong member 15; it goes without saying that the opposite tong member 15 can also similarly comprise two ball bearings 23. The ball 24 of the ball bearings 23 concerned engages with a groove 25 provided on the outer peripheral surface 13 of the bush-type lower blade 11, in order to bring about an axial form closure between the tong members 15 and the bush-type lower blade 11 in the direction of the lower blade shaft 10. It is possible with such a configuration to also correct the bush-type lower blade 11 in its position on the blade shaft 10 when the lower blade 11 is rotating, because the rotating lower blade 11 can run in the ball bearings 23.

As seen from Figure 5, the gripping device with the tong members 15 can also impinge in a plane offset by 90 degrees relative to the impingement area 13 in Figures 1 to 4, namely on the front ends 26, 27 of the bush-type lower blade 11, wherein the outer front end 26 rests against the front edge of the piercing die bush 20 and the front end 27 is the front end formed by the production of the cutter groove 19 and of the cutting edge 12. In this embodiment also the positional correction of the lower blade can be undertaken in a simple manner.

On the carriage 14 are further disposed two optical lasers 17, 18, which comprise respectively a transmitter for a laser beam and a receiver for the optionally reflected laser beam; the lasers 17, 18 are so aligned that the laser beams emitted by them are spaced a short distance apart in the plane determined by the piercing die bush 11, for example of the order of magnitude of 0.1 mm or less; this distance can be set at will according to the tolerances required by the machinery. The purpose of the twin arrangement of the lasers 17, 18 is to determine unequivocally the position of the cutting edge 12, which does not protrude further physically from the smooth outer peripheral surface 13 of the bush-type lower blades 11, but can be detected only through the interruption of the smooth outer peripheral surface 13 by the blade grooves 19.

Specifically, if, during the travel of the carriage 14 for the determination of the position of the cutting edge 13, both lasers 17, 18 display or else do not display a reflection in concert, the position of the carriage 14 is therefore determined either above the outer peripheral surface 13 of the bush-type lower blades or in a region between two bush-type lower blades, wherein no cutting edge 12 is encountered in these areas. Only when the laser 17 reports a reflection and the laser 18 does not report a reflection is the position of the cutting edge 12 unequivocally detected; if conversely the laser 18 shows a reflection and the laser 17 does not, then with such a signalling message the front edge 20 of the piercing die bush 11 is indicated; a reverse arrangement can also be provided.

After a re-grinding of the cutting edges 11 of several bush-type lower blades 11 accommodated on a lower blade shaft 10 has been carried out, the bush-type lower blades 11 are slipped onto the lower blade shaft 12 in any order.

The carriage 14 is slid with its optical lasers 17, 18 onto the slipped-on bush-type lower blades 11, and in so doing the position, referred to a zero point, of the cutting edges 12 of the individual bush-type lower blades 11 is accurately determined, and the corresponding values are inputted into the controller.

Since the values for the cutting width to be set are likewise contained in the controller, the controller can determine the degree to which the respective bush-type lower blade 11 with the associated cutting edge 12 has to be displaced; thereafter the displacement operation is carried out through renewed displacement of the carriage 14 with connection of the bush-type lower blades 11 by means of the tong members 15, wherein the bush-type lower blades 11 are displaced in accordance with the preset value resulting from the controller. The displacement of the carriage 14 can moreover be performed automatically or by hand, wherein a numerator can also be provided on the carriage for indicating the distance covered. A further control run of the carriage 14 with the lasers 17, 18 as a follow-up to the adjustment of the bush-type lower blades is possible. The signals supplied by the optical lasers 17, 18 or comparable sensors can also be used in addition or alternatively to the width of cut setting for the use of direction indicators, wherein these direction indicators indicate to an operator the displacement direction, preferably via so-called LEDs.

Claims

1. Device for the positioning of lower blades on length wise cutting machines, wherein the lower blades are displaceably mounted on a lower blade shaft, are single- or multi-cut and are of bush-type construction, and wherein the positioning device comprises a carriage, which can be displaced on a linear guide aligned at a distance parallel with the lower blade shaft by means of a displacement device to be connected to the bush-type lower blade, and a controller for setting the distance between the cutting edges of the bush-type lower blades, characterised in that the displacement device is constructed as a gripping device (15) impinging on the bush-type lower blade (11) and there is disposed on the carriage (14) bearing the gripping device (15) an optical laser (17, 18) or sensor for detecting the position of the cutting edges (12).

2. Positioning device according to claim 1, characterised in that the gripping device is constructed as a pair of tongs with two tong members (15) which impinge on the front edges (26, 27) of the bush-type lower blade (11).

3. Positioning device according to claim 1, characterised in that the gripping device (15) impinges non positively on the smooth outer peripheral surface (13) of the bush-type lower blade (11) and is constructed as a pair of tongs with two tong members (15) embracing the bush-type lower blade (11).

4. Positioning device according to claim 3, characterised in that the tong members (15) display on their inner sides (16) resting against the outer peripheral surface (13) of the bush-type lower blade (11) a frictional configuration (22).

5. Positioning device according to claim 3, characterised in that the bush-type lower blade (11) displays on its outer peripheral surface (13) in the impingement area of the tong members (15) a frictional configuration (22).

6. Positioning device according to claim 3, characterised in that the tong members (15) are provided on their inner sides (16) coming to rest against the outer peripheral surface (13) of the bush-type lower blade (11) with at least one ball bearing (23) whose ball (24) engages with a groove (25) formed in the outer peripheral surface (13) of the bush-type lower blade (11).

7. Positioning device according to one of claims 1 to 6, characterised in that two optical lasers (17, 18) are disposed on the carriage (14) in such a way that the laser beams emitted by them are spaced a short distance apart in the area of the bush-type lower blades (11) to be scanned.

8. Positioning device substantially as herein described with reference to the accompanying drawings.