DE1752006C3 - Control for a shear line for trimming and dividing sheet metal, especially heavy sheet metal - Google Patents

Description

The scissors control according to the invention is expedient in detail according to the features of Claim 2 formed

Since the control according to the invention - if they are the same when a specified finished length is present or only a little larger than one or more times the feed interval - leads to the fact that the sheet feed takes place once more than otherwise necessary and ~ by starting and braking a certain time is lost, it is within the limits men of the invention that the pulses to stop the sheet feed by zero comparison in the first Comparison device automatically triggers a cutting stroke of the dividing scissors and the drive of the sheet metal feed during the working cycle of the dividing scissors is electrically blocked This saves valuable time.

In the drawing is an embodiment of the control of a scissors line in connection with the Shear line of short overall length after the starting point of the invention shown, u.id shows • Fig. 1 is a side view of a double trimming shear and a dividing shear set up straight behind it,

F i g. 2 is a plan view of the switch in a roller ₅ a built scissor unit,

3 shows an electrical circuit diagram for the arbitrary and controlled stopping of the drive rollers or feed means,

4a and 4b show two representations of a metal sheet with the information required to understand the control according to the invention for setting the desired sheet metal length and

F i g. 5 is a block diagram of a control system for shortening a penultimate feed interval as well.

1 and 2 show a displaceable trimming shear D set up within the shear line with the roller table rollers 2, as well as a stationary trimming shear D. which, positioned opposite one another, represent a double trimming shear. In the area of double Trimming shears, the sheets are clamped by pairs of drive rollers 4 and 6 and pushed forward with absolutely correct edges, after which the continuous Trimming shears make their cuts.

Shortly behind the double trimming shear, a partial shear T is set up, which has a pair of driving rollers 8 behind the knife level in order to pull through the last sheet metal end when it has left the driving rollers 6. At least the roller table rollers within the dividing scissors T are namely loose rollers. A pair of feeler rollers 1 · in front of the knife level, one of which is driven, is used to measure the sheet length passing through, as will be explained below. 12 is an end pusher of conventional design. In order to still be able to advance the metal sheets with their rear ends at the correct edges when they have left the pair of driving rollers 4, brackets 14 with guide rollers 16 are arranged on each trimming shear. The sheets are thus divided in the dividing shear T in the clamping by the feed and guide means 4, 6, 16 of the double trimming shears.

The dividing scissors T are so-called roll-cut scissors with an upper knife that moves along the path and has a curved cutting edge.

An advantageous mode of operation of the double trimming shear / dividing shear unit according to the invention is illustrated with the aid of the circuit diagram according to FIG. 3 explained. Here, 32, 34 mean the power lines an auxiliary control circuit, the line pair 36 the network for operating the motors T of the dividing shears and the line pair 38 the network for operating the motors V of the feed means, ie the drive roller pairs 4, 6, 8 and 10 and the driven roller table rollers 2.

It has already been stated that the feed means are switched on intermittently, derived from the trimming shears D _{1 and £> j passing through.} For this purpose, a control cam disk 40 placed on a crankshaft of the trimming shears is used, which rotates in the indicated direction of rotation and is about to close a switch 41 via a button 42 during the return stroke of the blades of the trimming shears. In this way, a relay 44 is energized, which closes the switch 46 in the network 38 and switches on the motors of the feed means denoted by V. The switch 41 opens automatically under spring pressure when the cam disk 40 releases the button 42

Since the front end of the sheet must first be scooped up, it is provided that the feed means, which normally carry out a fixed feed path according to the knife length of the trimming shears, can be stopped at will. This has a push button 48 by which the relay 44 is de-energized even if the cam disk 40 keeps the switch 41 closed. By pressing the push button 48, not only does the switch 50 open for this purpose, but the switch 52 in the control circuit of a relay 54 also closes, which when energized closes the switch 56 in the network 36, whereby the motors designated by T are closed the dividing scissors are switched on. A holding contact, not shown, keeps the switch 52 closed and the switch St open until a working cycle of the dividing scissors has ended

With the execution of the first cropping cut, a length measurement must begin in order to advance a given sheet metal length into the fast shear. and regardless of how many strokes the double trimming shear executes. The feed means must therefore be stopped in a controlled manner according to the signal from a length measuring device.

Referring to FIG. 1 it can be seen that a of the feeler rollers 10 is connected to an encoder 58 which, depending on the number of revolutions, counting pulses representing a first signal proportional to the length of the sheet fed forward, to a first comparison device 60 forwards. A preselector 62 enters the comparison device 60 the pulse sum as a second signal proportional to a desired partial length. By im Comparison device 60, the first signal is continuously compared with the predetermined second signal is given by the comparison device 60 via the line 64 eir pulse to shut down the feed means if the comparison results in zero.

Returning to the circuit diagram according to FIG. ': it can be established that the line 64 carrying the stop pulse carries control current and is closed in the comparator 60 by a switch 66, the value zero of the target / actual value comparison is reached, ie the desired sheet metal length has passed due to the presetting in the device 62 When the switch 66 is closed, the relay 68 is energized, the switch 70 is opened and the switch 72 is closed; sen, which is in the loop 74 of the control line 7

The opening of the switch 70 has the same Effect as with push-button switch 50, i.e. h., The feed means are independent of the drive Trimming shears stopped. If the switch 72 is closed, then - as when closing the switch- ters52 - the relay 54 energized and the dividing scissors automatically switched on by the stop impulse. At the same time is through the currentless relay 44 of Feed drive blocked.

So that the length measurement begins exactly with the first crop cut, a branch line 78 goes from the control line 76 to a ballast 80 of the transmitter 5, which carries a voltage pulse when the switch 52 in the line 76 is closed by pressing the push button 48 to trigger the crop cut . This voltage pulse causes the gear 80 that the transmitter 58 passes the continuously emitted by a tracer roller It Undrehungssignale as the first signal during the next or of the cam plate 40 caused _ao feed interval of the first comparison device 60th

The circuit is perfected appropriate nor to the effect that the comparison device 60 shortly before the end of the set and actual values Vcrgleiches sends an impulse to a relay, which delays the advance _'s medium to creep speed, so that the sheets during final shutdown not by their Mass force continue to run.

As far as described so far, the control of the shear line ensures that the last feed interval can be shortened independently of the continuous drive of the trimming shears, namely independently of the revolutions of the cam disk 40. To explain this process, reference is made to FIG. 4a. Here a section of a metal sheet 81 is shown which has an indefinite length from the line 85 of a severing cut of the dividing scissors Γ. The cut along line 85 may have been arbitrarily initiated by pressing push button 48 (FIG. 3). The intermittent length measurement is enabled by the voltage pulse sent to the device via line 78. _{The feed intervals F 1} , V _x , F ₃ , F ₄ run one after the other.

L _F denotes the desired finished length of a metal sheet, in which a multiple of F does not fit, rather the partial cutting line 87 lies within the next feed interval _{K 5} , which must be shortened by the distance Δ F _5. This is done by the set-actual value comparison in the first comparison device 60, in which the actual value of the sheet length Fj + V ₂ + V ₃ + F ₄ + (F ₅ - Δ VΛ as the first signal is compared with the desired sheet length L _F as the preset second signal When comparing zero, the feed is stopped by closing the switch 66 in the device 6t and the dividing shears are set in motion, whereby control measures can still be taken to slow down the sheet feed via slow speed and the dividing shears just before the sheet metal comes to a standstill due to their inertia to turn on.

It can now happen that a desired sheet metal length is only slightly more than a multiple of the feed interval. In such a case it is not only difficult after the end of the last ⁶ S full feed _{interval F 4} to precisely drive the small remaining feed, there is also the risk that the cross knives of the double trimming shears D ₁ , D _{t will} find too little "meat" and slide off when the remaining feed is between zero and, for example, the sheet metal thickness, in order to specify a limit for the risk of slipping.

Such a case must be calculated in advance, since, for example, the difference between the second signal L _r and the first signal L _{ell of} the sheet length passed through can be continuously determined and examined whether there will be a difference L _F -L _elt between a full feed interval F and V + sheet thickness d lies. Reference is made to FIG. 4b. _{The trimming cuts corresponding to the feed intervals F 1} and F ₄ are drawn along the line 89 on the upper edge of the metal sheet 83. It can be seen that with a desired sheet metal length T. _r, after completion of the last full feed _{interval F 4,} only a residual feed F 'is required in order to still cut off the small seam piece 91. If V is less than the sheet metal thickness d, the difficulties mentioned arise, regardless of whether the severing cut with the transverse knife takes place immediately after the longitudinal cut or after the next working cycle of the trimming shears, at least with regard to the difficulty of advancing on small paths

So if a mathematical test results in the ratios according to FIG. 4 b above, then a control developed further within the scope of the invention according to claims 3 and 4 or according to FIG. 5 ensures that the penultimate feed step F ₄ is shortened so far that F ₄ + V is divided into two partial feeds, each of which is so large that the transverse knife safely cut into the trimming cut and / or the feed control including a delay before stopping there is enough time for the shutdown processes to proceed properly

At the lower sheet metal edge in Fig. 4b it is indicated that when the condition is met

L _F - L _elf > V ₄ ^ V ₄ + d

the second, preset signal L _F is corrected by - Δ V ₂ , ie a shortened first partial feed Δ F _{1 is} set, which is followed by the zero comparison in device 60, which is followed by the second partial feed Δ V ₂ , both of which are sufficiently large. After the first TeH feed ΔV ₁ , a shortened hem strip 93 is cut off, followed by a residual strip 97 in the double trimming shears.

The control required to shorten the penultimate feed interval is shown in the Embodiment Fig. 5. It can be seen that the elements 10, 58, 60, 62, 64, 78, 80 and the actual feed control 44, 46 and the dividing shear control 68, 72, 54, 56 are expanded by a device complex which is bordered by the dashed line 43

Furthermore, a pulse counter 45 for partial feed lengths is also shown which receives its pulses from the encoder of the measuring rollers 10 via line 47 and emits a pulse sum signal corresponding to the actual feed interval L _{fll via line 49.}

The additional elements within the line 43 initially include a difference device 61 for continuously mapping the difference L _F -L _ell (FIG. 4b) from the signals of the preselector 62 and the transmitter

58 as well as a second sounding comparator or a discriminator 63 for determining whether the condition at some point

L ₁ . - L _f "> V ^ V - \ - d

is fulfilled, that is, after a last feed, z. B. V ₄ , too small a residual feed V < d remains. If this is the case, an impulse is sent via the line 65 to the changeover switch 67 and switches the switch 69 from the normal position shown, secured by spring pressure or the like, to the contact 71. In the normal position of the switch 69, the control variable V, which corresponds to the full feed length and which is shown in FIG. 3 is introduced through the control disk 40, 41, connected via the line 73 to a third comparator 75 for zero comparison V = V _cll , whereby the normal feed control 44, 46 is actuated via the line 77 for full feed lengths. In addition, a line 84 goes from the feed device 40, 41 to a summation device 86 in which the value d coming from the preselector 88 is added to V. This sum V + d goes to the second comparison device 63.

In the switching position of the switch 69 on contact 71 there is a preselector 79 for the control variable of the shortened first partial feed length. ΐ V _{1 switched} to the comparison device 75. Since each time a feed is stopped, the feed control 44, 46 sends a pulse to clear the pulse sum in the counter 45 via the line 82, the line 49 constantly contains the actual value V _{efl of} the sheet feed within a feed interval. _{By comparing} this value V efl with the value Δ V ₁ , which is set to about half of a full feed interval V at 79, the third comparison junction 75 now delivers an early stopping pulse, so that the occupants only cut off the seam strips 93.

Soon after the partial feed Λ V _} starts, the diIleren / /. _; /.,. "In devices 61 and 63 less than uK V. ie the impulse going via line 65 goes out, switch 69 returns to the normal setting, and the control is set to" full feed intervals ". However, it is now overwritten by the zero comparison in the first comparison device 60, which _sends a pulse to both the feed control 44, 46 to stop the remaining feed AV \ and to the dividing shear control 68, 72, via the line 64 at L _F = L rlf. 54, 56 for triggering the Teilschniltcs supplies.

The control according to FIG. 5 in conjunction with FIG. 4b is based on the difference

ίο L ₁ . - L ,. "To conclude on a last, too small residual feed V ' and then to divide the remaining total feed into two partial feeds until the desired sheet length is reached. Of course, there are other ways of solving the problem of providing two last, roughly equal partial feeds for each finished length L _F , e.g. by calculating whether a comparison of L ₁ : with all possible «-fold feed intervals results in a remaining amount V that is less than

“O is an“ too small ”amount d . Generally speaking, the invention therefore comprises a controller according to claim 3.

Furthermore, the amount d was defined as the sheet thickness. If, however, the trimming shears do not have an inlet-side, but only an outlet-side cross knife (British patent specification 991 343), which means that the problem of the unsafe cross knife cut does not arise at all if the residual feed V is too small, then d becomes only from the point of view of setting a sufficiently long last one Partial feed selected. "Sufficiently long" is to be understood as a feed in which the feed motors are given time to travel from a constant speed upwards as a function of the path - namely through a setpoint / actual value.

Comparison, e.g. B. after L ₁ . = L cll - to be stopped in a targeted _{manner in such a way that the desired feed length is precisely obtained.}

In this respect, the special feed control according to FIG. 5 and claims 3 and 4 independently

of whether the dividing scissors are roll cut scissors or not, and whether the sheets are pushed forward by drive rollers be or otherwise, if only the scissors section without free outlet close behind the opposite one Trimming shears is arranged.

In addition 5 sheets of drawings

Claims (2)

I 2 Zyx (63) occurs when it is stated herein that the claims: Le ~ -Le "> V ^ .V - d 1. "Control for a scissors line for trimming 5 3. Control according to claim 2, characterized in that Raising and dividing sheet metal, in particular, indicates that the impulses for coaming their heavy plates, consisting of both sides of the sheet feed through zero comparison in The first comparison device (60) set up opposite the roller table has a cutting stroke of the Knife trimming shears with cross knives to the Tcüschere (T) trigger automatically and the Separation of the seam strips and a short io drive of the book feed during the work Distance downstream partial scissors, whereby the cycle of the partial scissors is electrically blocked
Sheet feed through at least one of the Knife movements of the continuously driven. NEN trimming shears depending on actuated pair of driving rollers or similar feed means: in normal 15 wise takes place equal intervals, which by will- The invention relates to a control for a Natural intervention by stopping the sheet metal shear line for trimming and dividing Feed can be shortened, with a measuring sheet metal, especially heavy plate, after the upper Richtuag to determine the partial scissors according to the term of claim 1. It is assumed that an initial crop cut in feed 30 that the scissors line from both sides of the roller table Sheet metal lengths passing at intervals and a long knife trimming unit set up opposite Device for path-dependent automatic shearing with transverse knives to cut off the hem Shut down the sheet feed and switch on the strip and from a short distance the partial scissors exist when the desired partial scissors are reached. Finished length, characterized by a. During the operation of such a scissors unit device (61, 63) for calculating the in advance, the following problem arises: As long as the desired final length (L _f ) that can be cut to length by the cut of the dividing scissors to achieve the desired finished length (L f) required feed interval (V) length of one or more times the normal feed interval, which is fixed for comparison of this last feed interval, below the interval with a predetermined minimum feed interval that is greater than the sheet feeder , by a sufficiently large amount deviates, thick (d) is, proportional value and with one cut the cross knives to cut off the seam device to lengthen the last pre-strip always into the full material. However, it is not possible to rule out the advance interval (V) at the expense of the penultimate one, that the desired finished length is only an advance interval (K ₄ ) in such a way that the 35 in each case is slightly greater than the single or multiple of the last two advance intervals the value of the fixed or set advance interval , predetermined minimum feed interval not so that there is a risk that the cross knife does not fall below. sufficiently far from the cross knife cutting edge of the 2. Control according to claim 1, start with a penultimate cut away, slide off and through an initial crop cut of the part 40 forcibly move the sheet in the longitudinal direction, scissors (T) switching device (10) for which the given finished length is no longer correct. In such cases, generating one of the sheet lengths advanced in one or even several intervals could no longer penetrate the material, but instead it (L _ell ) proportional first signal, a sudden increase in the horizontal Komwählgerät (62) for storage Bend one of the 45 components of the cutting pressure, which can break the desired finished length (L _f ), which is proportional to the two-transverse knife arrangement,
th signal and a first comparison device (60). It is the object of the invention to create the prerequisites for sheet metal presetting when comparing zero by means of control for generating a pulse to stop the technical measures, so that when a specified finish is drawn by a difference device for determination 50 length has passed through the double trimming scissors the difference between the second signal (L _F ) and the partial scissors has reached the cut, the cross and the first signal (L ,,,), a second measuring device of the continuously operated double trimmer: (63 ) to determine whether the cut-offs always find a minimum length of the seam strips for cutting, with which a normal cut £ _ £ "> V <LV - d ^5S can be expected. This task is performed by ^r '" ^ in the code of patent claim 1 is specified, wherein V the unabridged feed features solved by using an interval and d of the presetting lable minimum pre-calculation of the last value corresponding to the reaching of the feed interval (V) is the desired finished length required feed and a switch (67) for the temporary 60 interval by comparison with a predetermined switch-off of the control variable of the unabridged minimum feed interval, if necessary the feed interval (V ) of the feed control last feed interval is extended at the expense of the penultimate one and activation of a shortened feed interval. If the Dop feed interval (Δ V ₁ ) corresponding to the control variable set in pel-trimming shears then also for the last trimming of a preselector (79), 65 cut before switching on the dividing shear part which is greater than the minimum feed interval, cuts "into the void", the temporary switchover has been achieved so that the cross knives always cut a pulse from the second comparison device.