DE1752691A1 - Precision sheet metal shears for sheets of very different thickness - Google Patents

Description

Precision sheet metal shears for sheets of widely varying thicknesses The invention relates to precision sheet metal shears for sheets of very different sizes Thickness with a knife carriage along one over the whole cut surface fixing lower knife / movable upper knife.

A major problem in the construction of sheet metal snips of the type mentioned above, i.e. for sheets of very different thickness, is in the course of rationalization, i.e. when simultaneously taking into account the work results in terms of quality and speed, that other knife designs are suitable for thin sheets than for thicker ones Sheets.

It is known that scissors with a round upper knife make thick sheets cut worse than crank shears. The quality of a cut with a round The upper knife and the lower knife that runs through along the lower edge leaves improve so much that cuts at high speed and sufficient Precision can be carried out on thin sheets.

In the case of thick sheet metal, however, it is sufficient for many sheet metal processing requirements the quality of this type of cut does not compromise the cut.

Crank shears are therefore generally used for thick metal sheets, it being known that a complete crank shears with a cutting length shorter than the intended cutting length is guided along the desired cutting line and thereby executes a multi-stroke cut. These known scissors produce a very good sonicity even with thin sheet metal, but a low cutting speed, so that economic use of the scissors is called into question in many cases, especially in connection with sheet metal lines with the high cutting sequence required for thin sheets.

With all scissors it also takes place in the same way with increasing Sheet thickness a deformation of the upper edge of the cut surface in the sense of a rounding, d4 the sheet through the inclined both with crank knives and with circular knives The cut surface lying to the sheet metal surface from the plane into the angle of the cut surface is bent and in this area a plastic stretching of the edge areas takes place in which the surface of these areas with the beginning chip downwards is pulled. This phenomenon is more pronounced, the greater the sheet thickness, and in turn more strongly with circular knife shears than with crank shears. this has its cause on the one hand in the higher force to be expended when cutting thicker ones Sheets and on the other hand in the need to achieve a lower specific Cutting pressure with crank shears respectively. due to the greater depth of immersion with circular knives the angle between the cutting surface and the sheet metal surface becomes larger, and thus a stronger deformation up to the adaptation to the `Jinkel the cutting surface is required.

It is the object of the invention to provide precision sheet metal shears of the type mentioned to create that for sheets of different thickness from thin sheet metal to very thick container sheets an absolutely clean im Cross-section practically undeformed section with a section that depends on the sheet thickness maximum possible speeds generated, so that even high requirements a Cutting quality with high work performance are met.

According to the invention, this is achieved in that the support in A circular knife in front of the feed direction and a crank knife behind in the feed direction is arranged and circular knife and crank knife are mutually adjustable in height.

This arrangement according to the invention is not only available for the sheet metal area those at high speed working circular knife scissors and for Sheet metal for the thickness of the crank scissors alone at disposal _,:, sorle.-, in the middle and largest thickness range can be made stepped execution of the cut - regulation # tt m-. 1, x rice knife scissors, re-cut with crank scissors with a very good cut be carried out at a corresponding permanent speed.

In the case of relatively thin sheet metal, both for the circular knife scissors alone as well as for the curve scissors alone can be used with each of the scissors as well cutting that meets high quality requirements. For sheet thicknesses, in which the deformation described above would occur, however, is with the Circular knife made a preliminary cut, i.e. the material along the cutting edge cut through on the surface, so that when finished cutting with the crank shears the sheet metal surface is no longer drawn in, but when:; fitting the chip from the sheet metal surface respectively. the surface of the pre-cut to the angle of the,) cutting surface the knife tears off the chip full sheet metal without significant plastic deformation occurs.

With the scissors according to the invention, it is not just easy to get through the union of the two: types of hedgehogs on a common knife sledge one : 'Adjustment of the scissors overall to other sheet metal areas is possible, but it leaves surprisingly quiet at the same cutting speed and without additional Adjustment of the knife angle of the crank shears for all sheet thicknesses one uniform make good quality of cut.

To keep the mechanically movable parts of the knife as small as possible hold, the circular knife is preferably to adapt to different disc diameters and different sheet thicknesses adjustable in height on the support while it to move out of the work area, in the event that the crank scissors so is to be used, in the direction of an axis of rotation in and out of the working position is. For better execution of the cut, especially for improvement The cutting process when pre-cutting with the circular knife is preferably the cutting surface of the circular knife in per se known tit rising away from the cut surface in the sheet metal aus7e trains.

This can be done in a known (way either by corresponding 1: egelige Formation of the cut surface or achieved by tilting the circular knife will.

Since when using the circular knife for pre-cutting the necessary Inclination angle, the lifting height and accordingly the Habzahl lower than with -. 11er1 Sheet metal .: is and also in certain applications eire approximately continuous The working speed of the scissors changes with the sheet thickness, can according to the invention, the crank knife to change the skew angle of Cut against the plane of the sheet; the lifting height and the number of strokes are adjustable be. To make a precision cut, the kerf, i.e. the Distance between the cut surface parallel plane through the upper and lower knife essential. Since with the scissors according to the invention not only how with normal scissors working with a knife along a lower knife the pure horizontal distance at right angles to the cut surface, but the corresponding one Distance between the two; scissors kept exactly constant over the working length of each scissor has to be, a particularly precise one is however relative for the scissors according to the invention simply and easily adjustable guide of the knife carriage required. These According to the invention, the knife carriage is preferably guided by that the knife carriage on each two roller guides horizontally respectively. vertical against Pairs of rails is supported on the longitudinal frame against the machine bed and each the main load directions counteracting rollers against the associated guide rails are elastically biased. The horizontal ones are preferably used for adjustment Roller guides acting in the main load direction perpendicular to the assigned rails adjustable. This arrangement according to the invention takes place one form-fitting precise guidance entll.:.g: ._. horizontally directed against the knife pressure Guide rail, with the opposite `` 'olle for a constant safe Anl' '-, e sc @gt that certain deviations from which they are forced by .__ working tolerances . @ f i. @ @: ._ @ -_ - not for taking off from the lead, and thus to a greater tilting of the i @: e @ sc? -slide in a horizontal plane leads to what "I-1 a significant difference in the gap width of the knife on the one hand and the crank knife "nderers (-. ts would be evoked.

In order to avoid the cut surface through the cutting pressure components occurring forces on the I (esser and thus a torque on the To avoid the sledge, it is preferable to use the knife sledge with a Guide roller anoranunein a fiälrun @ arranged on the underside of the counter knife; s-rail supported in the known tit. By this according to the invention Arrangement is a precision sheet metal shears created, the sheets practical all thicknesses that can be cut with such scissors for thin sheet metal up to the thickest Container sheet much cleaner and in most cases faster than known ones Scissors of a comparable design cut.

The invention is illustrated below with reference to the drawings of exemplary embodiments explained in more detail.

In the drawings: Fig.l shows a schematic side view the knife part of a pair of scissors according to the invention, FIG. 2 is a view similar to FIG on a curved shape of the scissors, Figure 3a shows a cross-section through a sheet metal edge, as produced with conventional scissors with an unfavorable thickness ratio to the scissor type will, 3b shows a Cu section through the; ch ~ @ ttbereic; @ one Sheet metal when pre-cutting with a circular knife, and 2ig.4 - a schematic cross-section lu - :: '- a `) chere according to the invention.

The "chere consists of a bed 1 with a LänF-sträger 2, on which The top of the shear table 3 with the lower knife 4 lies. Lesson Eater 4 is running across the entire length of the cut edge. .? n the opposite side of the l, laschinenbette @ i a longitudinal beam 5 is supported, the @ 1 c f '' * b-rur, .-- @ ~, for the knife carriage 6 or serves as Fru = :: @ itself. So it is known support a round support shaft over the length of the machine bed which the knife carriage is supported on the rear side while it is on the front with rollers on a corresponding guide track on the front longitudinal member 2 supports. These designs of scissors are known and not shown in the drawings or only shown schematically. When in Fig.l schematically Precision sheet metal shears shown is a circular knife 7 adjustable in height by means of of a support on the knife carriage 6. The circular knife is outside # -. lb between a Zage at which it is completely extended upwards from the work area until in a moment in which it intersects the lower knife in its lowest area, adjustable by means of known devices, e.g. spindle drive or eccentric.

In the cutting direction behind the direction indicated by an arrow behind the circular knife is a crank shears 8, which are connected to cranks 10 via crank arms 9. The stroke of the crank 10 corresponds to the maximum cutting height of the crank knife. It is not necessary to move the crank knife out of the cutting area, because when the circular knife is fully working, the cutting edge of the stationary crank knife slides along the cutting surface on the sheet metal 11, while in all other cases in which the circular knife pre-cuts or does not work at all, the crank knife itself Operation must be.

In the exemplary embodiment shown in FIG. 2, the disk knife is located l with its' delle 1'2 on an eccentric 13, through the rotation of which its H @> bright position the axis of rotation 12 to the different knife diameters and in question Sheet thickness is adjustable. The circular knife is also in the direction of its axis 12 can be extended horizontally from the work area when the crank knife is working alone. In this embodiment, the crank knife 14 to adapt to different Cutting angles (, stroke height and number of strokes driven by hydraulic cylinder 15. The hydraulic cylinders are coupled together so that they are simultaneous are acted upon and cause a parallel displacement of the crank knife, wherein at the same time as changing the angle oC, the corresponding degree of filling of the loading area can be set differently for both hydraulic cylinders. To those in the direction of the cut To absorb horizontal forces acting on the knife 14 is also possible on the knife another link 16 hinged with one end, the other with its other end at the Knife carriage is stored.

Fi'g.3a shows the sheet metal 11 with a cut surface 17, which on a conventional crank shears or circular knife shears was cut. It is through the .Anpassung chip from the sheet plane in the area of the cutting edge, ie, the A bbiegung retracted the metal sheet on its upper side to a rounded portion 18 at the angle 0C9. This rounding is the stronger, the larger the Winkelacbezw. the corresponding angle of a circular knife and the greater the sheet thickness. In a large number of applications, such a deformation of the cutting edge makes reworking of the sheet necessary before further processing.

In Figure 3b is the invention by the pre-cutting with the Circular knife scissors achieved effect shown.

The plate 11 according to Figure 3b is along the cutting surface 19, which is dashed is shown, because the sheet has not yet been cut at this point, first pre-cut by the circular sea 7, its cutting surface 20th away from the cut surface 19. The circular knife is very little in the sheet metal surface is immersed, is corresponding to the @ ^ linkel, -C Cutting angle of the circular knife, i.e. the angle between a tangent at the entry point the knife edge on the sheet metal surface and this itself very low and the the deformation producing the bend 18 is therefore practically negligible. However, since the upper edge area of the cut surface 19 already from the chip section of the sheet metal is separated, no tensile forces in the plane of the sheet act during finish cutting more on the sheet surface and the sheet is therefore no longer closed at the edge a rounding 18 drawn in. When finishing cutting with the circular knife, the circular knife would at a much earlier point in time, i.e. at a much steeper point of the circumference of the circular knife immerse into the sheet metal and thus the dem Winkelas of the crank knife according to Fig. 2 comparable angles can be considerably larger, so that, as with the crank knife, a rounding 18 would then be produced. at the scissors shown in cross section in FIG. 4 is the machine frame as at the beginning explained trained. The support beam 5 lies on a console-like increase.

hungen 21 of the machine bed 1 and is provided with guides 22, 23, 24 and 25 which have guide surfaces lying approximately at right angles to each other. Rollers 26, 27 run off the guide surfaces of the guide rails located in the main load directions, but are mounted in the knife carriage 6 in a form-fitting manner in the roller plane towards and away from the guides. On the oppositely directed guide rails 22, 24, rollers 28, 29 run off, which are mounted on the knife carriage 6 at right angles on the associated rails, under the bias of a spring. At the. A guide rail 30 is also arranged on the front side of the machine bed 1, on which a roller 31 is supported, which is movably supported in the knife carriage 6 at right angles to the guide rail under the pretension of a spring. A further guide rail 32 is arranged on the underside of the table 3 carrying the lower knife 4, against which a roller 33 is supported, which is mounted positively and possibly at right angles to the guide sscniene adjustable. Through this role: the torques transferred to Pig. 4 by the knife pressure on the knife slider ö by the pressure of knife 8 on the knife carriage clockwise are accepted, so that these torques do not cause any movement of the knife carriage.

Furthermore, a spur gear 34 is mounted on the knife carriage 6, which driven by a drive motor, not shown, via a reduction gear and against one next to the guide rail 32 on the underside of the scissor table 3 lying Zahr_sU-2rge 35 unrolls. The knife carriage 6 is along the Guide beam 5 and the scissors table 3 with the lower blade 4 moved.

Claims (7)

A ns p r ü che 1, Precision sheet metal shears for sheets of very different thickness with on a knife carriage along a fixed lower knife moving over the entire cutting length, characterized in that a circular knife is arranged on the support in the feed direction at the front and a crank knife in the feed direction behind it and Circular knives and crank knives are adjustable in height against each other. 2. Precision tin snips according to claim 1, characterized in that the circular knife (7) is adjustable in height 2. is mounted in the knife carriage (6) and in the direction of its axis of rotation (12) in and is displaceable from the working position. 3. Precision sheet metal shears according to claim 1 or 2, characterized in that the cutting surface (20) of the circular knife (7) in af known! quietly from. the cut surface (19) on the sheet increases away 4th Precision sheet metal shears according to claims 1 to 3, characterized in that the crank knife (14) to change the angle (., X.) Of the cutting edge against the plane of the sheet (11), the stroke height and the stroke rate is adjustable. 5. Precision tin snips according to one of the preceding claims, characterized in that the T-Zesserschlide (6) on two roller guides (27,2.9 and 26,28) horizontally and vertical against Pairs of rails (25.24 or 23.22) on the longitudinal frame (5) against the machine bed (1) is supported and the respective roles counteracting the main load directions (28 and 29) are elastically pretensioned against the associated guide rails (22, 24) are. 6. Precision sheet metal shears according to .'nspruch 5, characterized in that at least the horizontal Guide rail (25) is adjustable. 7. Precision tin snips according to any one of the preceding claims, characterized in that the knife carriage (6) with a guide roller counter (33) against one on the underside of the Counter knife arranged guide rail (32) is supported in a known case.