EP0860248A2 - Pressure bar for a shearing cutter - Google Patents

Abstract

The shears have an under blade and a relatively moveable upper blade. The holding-down device consists of a main carrier (9) and an extendable holding-down bracket (10) and is adjustable between two stages. It is lowered by a main stroke into a blocking position, in which the actuator cylinders are relieved and only the holding-down bracket is adjustable relative to the main carrier by a short pressure stroke (h). The actuator cylinders are connected to the main carrier via articulated actuator levers. Two horizontal cylinders, esp. compressed air cylinders, are fastened at a relative distance to the top of the machine frame.

Description

The invention relates to a hold-down device for scissors with a lower knife and a relatively movable, possibly designed as a roller knife Upper knife, especially for cutting textile or steel cord tapes, arranged above a cutting table in the guides of a machine frame is vertically displaceable via the actuating cylinder to the material to be cut Press the cutting table or the lower knife.

A major problem with such hold-downs is that they are used a relatively large clamping forces to exert any warping of the Material to be cut, in particular the fairly soft unvulcanized cord straps, to prevent when cutting and thus to achieve smooth cutting edges that but on the other hand, the actuating cylinders can not be hydraulic cylinders, because at never the risk of leaks and thus oil dripping can be excluded with absolute certainty. Oil is not allowed under any circumstances get to such unvulcanized cord tapes, otherwise the corresponding ones Batches can no longer be used for tire manufacture. Takes but if you only use compressed air cylinders, then the necessary clamping forces can be achieved not only difficult to achieve. In addition, you then need a lot of cylinders and with it too much air.

The invention is therefore based on the object of a hold-down device at the outset mentioned type so that with simple, safe construction and under Avoiding high-pressure hydraulic cylinders a safe and quick It is possible to jam the material to be cut on the cutting table.

To solve this problem, the invention provides that the hold-down device consisting of a main beam and a hold-down bar that can be opened opposite it consisting of two levels is adjustable, with a main stroke in a blocking position relieving the actuating cylinder can be lowered, in the only the hold-down bar over a short pressure stroke in relation to the main beam is adjustable. The hold-down with is not yet issued through the main lift Hold-down bar over a considerable displacement distance between the upper non-use position in a lower, a few millimeters above Position to be cut ends shifted and locked so that the next Extend the hold-down bar by this short remaining distance then strong back pressure forces do not act on the actuating cylinder can, but be intercepted via the blocking device.

In a further development of the invention, this can be achieved particularly simply by that the actuators over against each other in the raised rest position angled, articulated levers connected to the main beam are, the cylinder-side upper lever around a fixed pivot point on the machine frame vertically above the articulation point of the second lower control lever is pivotable on the main carrier, and the dimensions are selected so that the control levers reach a stretched position at the end of the main stroke. Here then the articulation point of the two levers lies exactly on the line between the fixed pivot point of the upper control lever and the lower pivot point of the lower control lever on the main beam, so that back pressure forces completely from the fixed Pivot point in the machine frame and none at all Can have an effect on the actuating cylinder. So is lowered from this Position of the main beam, the hold-down bar up to the short remaining stroke extended to be pressed onto the material to be cut, so that they are retroactive Pressure forces only in the upper articulation points on the machine passed and the actuating cylinders have for the actual pressurization of the Cuttings have no function at all and can therefore be relatively weak and be designed as a compressed air cylinder.

It is preferable to have two spaced actuating cylinders lying horizontally Attach to the top of the machine frame.

To achieve the desired high contact pressure of the hold-down bar you can in a further embodiment of the invention two-armed, strongly reduced swivel levers be provided with separate actuating cylinders, the Swivel levers prefer toggle levers with a long, essentially vertical one Actuating arm and a substantially horizontal one, on the hold-down bar articulated pressure arm, which are about axes parallel to the longitudinal axis of the hold-down bar are hinged to the main beam. Depending on the interpretation of the gear ratio between the length of the actuator arm and that of the pressure arm there is a corresponding translation of the force of the actuating cylinder, so that even when interpreting these actuating cylinders as relative - at least in comparison to hydraulic cylinders - weak pneumatic cylinders very high pressure and clamping forces can be achieved on the material to be cut.

The actuating arms are in the knee lever training mentioned above preferably over essentially horizontal, lying in the plane of the toggle levers Actuating cylinder pivotable at the upper end of the main carrier.

In a further development of the invention, the hold-down bar can be equipped with an exchangeable, preferably non-stick coated, protruding wear bar be provided alone on the material to be cut substantially linear rests, so that an exact, the desired cutting edge very closely adjacent Clamping is possible.

Finally, it is also within the scope of the invention to hold down the hold-down bar to attach their longitudinal axis to the pivoting levers so as to be pivotable.

Fig. 1

eine Seitenansicht einer Rollenschere mit einem erfindungsgemäßen Niederhalter,

Fig. 2

eine Ansicht der Rollenschere in Richtung des Pfeils P in Fig. 1 parallel zur Einlaufrichtung des Schneidgutes in der angehobenen Stellung des Niederhalters, wobei alle diejenigen Teile der eigentlichen Rollenschere mit Ausnahme des angedeuteten Untermessers weggelassen worden sind, und nur die den Niederhalter betreffenden Teile gezeigt sind,

Fig. 3

eine der Fig. 2 entsprechende Ansicht des Niederhalters in der um den Haupthub abgesenkten Position,

Fig. 4

einen vergrößerten Schnitt längs der Linie IV-IV in Fig. 3 in der abgesenkten Position des Hauptträgers des Niederhalters, jedoch angehobenen Position der Niederhalterleiste,

Fig. 5

einen der Fig. 4 entsprechenden Schnitt in der abgesenkten Klemmstellung der Niederhalterleiste, und

Fi.g 6

einen vergrößerten Schnitt längs der Linie VI-VI in Fig. 3 zur Verdeutlichung der Schwenkverstellbarkeit der Niederhalterleiste.

Further advantages, features and details of the invention result from the following description of an exemplary embodiment and from the drawing. Show:

Fig. 1

a side view of a roller shear with a hold-down device according to the invention,

Fig. 2

a view of the roller shears in the direction of arrow P in Fig. 1 parallel to the direction of entry of the material to be cut in the raised position of the hold-down device, all those parts of the actual roller shear with the exception of the indicated lower knife have been omitted and only the parts relating to the hold-down device are shown ,

Fig. 3

2 corresponding view of the hold-down device in the position lowered by the main stroke,

Fig. 4

3 shows an enlarged section along the line IV-IV in FIG. 3 in the lowered position of the main support of the hold-down device, but in the raised position of the hold-down device,

Fig. 5

4 corresponding section in the lowered clamping position of the hold-down bar, and

Fi.g 6

an enlarged section along the line VI-VI in Fig. 3 to illustrate the pivoting adjustability of the hold-down bar.

The roller shear shown in Fig. 1 is fastened with a machine frame 1 rigid lower knife rail 2 and a cutting head 3 provided which a roller knife 4 is attached by the in guides 6, 7 in the machine frame movable cutting head along the lower knife 2 is movable to the material to be cut between them, in particular a textile or steel cord tape, to cut off. In order to hold the material to be cut exactly during the cut, so that it cannot warp, is only schematically indicated in FIG. 1 Hold-down 8 provided. This hold-down 8 is based on the figures 2 to 6 explained in more detail below.

The hold-down 8 comprises a main support 9 and one opposite to this hold-down bar 10, which can only be raised by a small stroke, which ultimately with the Edge of a replaceable wear strip 11, which is preferred is non-stick coated, the material to be cut from above onto the lower knife 2 (figures 4 and 5). The hold-down bar is thus when the lower knife is reground readjustable. The main carrier can preferably have two as a compressed air cylinder extendable actuating cylinder 12 between the rest position shown in Fig. 2 and the lowered operating position shown in FIG. 3 can be adjusted. The adjustment movement the actuating cylinder 12, lying horizontally at the upper end of the machine frame 1 are arranged, an upper adjusting lever 13 and a lower control lever 14, which in the rest position (Fig. 2) against each other are angled. The fixed pivot point 15 of the upper control lever 13 on the machine frame 1 lies exactly vertically above the pivot point 16 of the lower control lever 14 on the main support 9 and the lengths of the control levers 13, 14 are selected so that after completion of the main stroke, i.e. the shift of 2 in the position of FIG. 3, the pivot point 17 of the Adjustment lever to each other exactly on the connecting line of the pivot point 15 with the Articulation point 16 lies. This means that in this position everyone from below directed reaction forces on the main support 9 due to the below Extension of the hold-down bar 10 to be described in the fixed pivot point 15 are intercepted and react no reaction forces on the actuating cylinder 12 can.

At 18 and 19 you can see side guides for the main beam 9, in which this is guided in the machine frame 1 during the height adjustment.

The hold-down bar 10 is parallel to the main support 9 with the aid of a plurality of spaced, designed as a toggle lever 20 suspended. Everyone this pivot lever comprises a substantially vertical long one Actuating arm 21 and a short lower pressure arm 22 with an intermediate one Swivel axis 23 parallel to the longitudinal axis of the hold-down bar. Around this pivot axis 23 on the main support 9 is the pivot lever 20 with the aid of a Actuating cylinder 24 pivotable, corresponding to the very different Lengths of the actuating arm and the pressure arm a strong pressure boost the force of the actuating cylinder. The actuating cylinder 24 itself lies essentially in the plane defined by the arms 21 and 22 of the corresponding one Swing lever 20 is spanned, and essentially horizontally at the upper end of the main beam 9. When extending the pistons of the Actuating cylinder 24 is a small residual stroke h for jamming of the material to be cut on the lower knife, necessary display of the hold-down bar down towards the main beam 9.

Due to the pivotability of the hold-down bar 10 about its longitudinal axis the pivoting position of the hold-down bar 10 is set via adjusting screws 25, so that the hold-down bar 10 with its non-stick coated wear bar 11 is very easy to readjust even with regrinded bottom knife 2.

The invention is not restricted to the exemplary embodiment shown. Crucial is that the hold-down consists of two parts, the first of which experiences a large main stroke H of the vertical adjustment movement, but through appropriate design of a blocking device no forces on its actuating cylinder retransmitted. The actual pressure movement takes place through a hold-down bar, which only has to carry out a very small remaining working stroke h and therefore can work with a significant power transmission.

Claims (10)

Hold-down device for scissors with a lower knife and one relative to it movable, possibly designed as a roller knife, upper knife, in particular for cutting textile or steel cord tapes over a Cutting table arranged in the guides of a machine frame vertically is displaceable via the actuating cylinder to bring the material to be cut to the cutting table or to press the lower knife, characterized in that it consists of a main carrier (9) and an extendable hold-down bar (10) is adjustable in two stages, with a main stroke (H) into one the setting cylinder (12) relieving blocking position can be lowered in the only the hold-down bar (10) over a short pressure stroke (h) opposite the main carrier (9) is adjustable. Hold-down device according to claim 1, characterized in that the actuating cylinder (12) via angled towards each other in the raised rest position, hinged adjusting levers (13, 14) with the main carrier (9) are connected, the actuating cylinder-side upper actuating lever (13) by one fixed pivot point (15) on the machine frame (1) vertically above the Articulation point (17) of the second lower actuating lever (14) on the main carrier (9) is pivotable, and the adjusting lever (13, 14) at the end of the main stroke (H) in reach a stretched position. Hold-down device according to claim 2, characterized in that two spaced apart Actuating cylinder (12) lying horizontally on top of the machine frame (1) are attached. Hold-down device according to one of claims 1 to 3, characterized in that that the actuating cylinders are compressed air cylinders. Hold-down device according to one of claims 1 to 4, characterized in that that the hold-down bar 10 via two-armed, strongly reduced swivel levers (20) is connected to separate actuating cylinders (24). Hold-down device according to claim 5, characterized in that the pivot levers (20) Toggle with a long, essentially vertical operating arm (21) and a substantially horizontal one, on the hold-down bar (10) articulated short pressure arm (21), which are about pivot axes (23) parallel to the longitudinal axis of the hold-down bar (10) on the main beam (9) are articulated. Hold-down device according to claim 6, characterized in that the actuating arms (21) each over essentially horizontal, in the plane of Operating cylinder (24) on the toggle lever at the upper end of the main carrier (9) are pivotable. Hold-down device according to one of claims 1 to 7, characterized in that that the hold-down bar (10) with an exchangeable, preferably non-stick coated, Wear strip (11) protruding downwards is. Hold-down device according to one of claims 5 to 8, characterized in that that the hold-down bar (10) can be pivoted about its longitudinal axis is attached to the pivot levers (20). Hold-down device according to one of claims 5 to 9, characterized in that that the actuating cylinders (24) are compressed air cylinders.

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