EP1039010B1 - Process and sewing unit for incorporating extra width - Google Patents

Description

The invention relates to a method and a sewing unit for Incorporation of fullness in a sewing material layer according to the generic term of Claim 1.

From the PFAFF information leaflet "PFAFF 3811", print date 04/89 several versions of one called an integrated sewing station Sewing unit known for incorporating fullness in a sewing material layer. In this sewing work, also known as pre-gathering, the Sewing material layer by the combined advancement of one with a basic stitch length working main carrier and at least one compared to this differential feed dog performing larger feed steps ruffled or gathered and this state through held a seam, possibly with a stabilizing tape is sewn on.

The degree of pre-gathering or the gathering dimension can be determined by a Set the differential stitch actuator. Depending on the equipment of the machine the differential stitch actuator is either by hand or by a electrically driven actuator operated, the twenty sensor buttons are assigned, each representing a specific gathering value. In a first version, the required gathering values can be successively recall. In a second version, pressing a Hand button two preselected gathering values alternately during the sewing process be retrieved. In a third version, programs with a larger number of different gathering values are stored, which in turn during the sewing process by pressing one Hand key can be called up one after the other.

In all cases, however, the operator must achieve the desired target length of the sewing material layer or a multi-width range select a suitable shirring value. An experienced one Operator will sometimes succeed at first. Nevertheless she also has to sew a test seam in order to use the finished result to be able to determine whether the selected gathering value is correct or incorrect was. However, an inexperienced operator is usually the only find the correct shirring value after trying it out, whereby time is lost and rejects are produced.

The invention is based, a method and a task To create a sewing unit by which the determination of the proper Incorporation of fullness required gathering values and if necessary the Determining the length of a fullness section is simplified. The Task is characterized by the characteristics of the sibling Process claims 1 and 2 and the device claim 5 solved.

The invention is essentially based on the idea by which the Computer assigned to the sewing machine from the initial length and the target length the layer to be pre-crimped for the incorporation of the To calculate the fullness of the required gathering value. This current shirring value is either immediately with the help of the actuator used to set the differential stitch adjusting device, or first inserted in a sewing program and in a data memory filed from which it is sewn either by pressing a button or after a specified number of stitches has expired and then also for setting the differential stitch control device is used.

Unless the length of a fullness range is manual or determined by stitch counting during a teach-in mode, but when creating a program to be formed by data entry is determined, perform in the features e, to g, of claim 1 specified measures make another important contribution to solving the Task. By considering the slip of the carriers, d. H. the difference between the set and the actual Feed value, the size of the slip with the size of the calculated current gathering value increases, can now in advance exactly calculate the number of stitches that arise when sewing a full-width area results and is used to determine the end point.

In the solution variant specified in claim 2, the taking account of the slip value-dependent slip of the transporters Correction value used to advance the feeders so far to increase that the slip is compensated. This leads to from the target length of the sewing material layer and the value of the basic stitch length immediately gives the actual number of stitches.

EP 124 211 B2 describes a method and a sewing unit for automatic feed control known, at or at Sewing a sleeve into an armhole at predetermined seam intervals in the Sleeve fullness is incorporated by a top feed dog executes larger feed steps compared to a sub-feed dog. For this purpose, the sewing unit works with an "adaptable" Control, d. that is, after programming the required The control saves additional amounts when sewing by stitch counting the length of the respective fullness sections. So even with the by the EP-B2 known sewing unit in sections in a sewing material layer If the fullness is incorporated, the two can still be used Do not easily compare machines or sewing processes.

This is partly due to the fact that the inventive Sewing unit the fullness in a single, on the smooth The stitch plate of the sewing machine is moved along the material layer while in the known sewing unit in one of two superimposed, mutually braking material layers happens. Therefore, the movement conditions of one sewing unit cannot be transferred to the other sewing unit. Because beyond that sleeve sewing generally with a larger number of the same, only differ in the clothing size of clothing done, it lends itself to the size of the sewing for the various Multi-width sections do not require multi-width amounts from select the respective operator of a sewing unit and then to be confirmed by trial sewing, but these activities to be carried out centrally by a work planner or work planner, the then also finished programs for the whole Process of a sleeve sewing process created.

Pre-ruffling individual layers of material, on the other hand, is very various fields of application applied, e.g. B. in shoe manufacturing, the upholstery industry and clothing production at Blouse and clothing processing, whereby often only small lot sizes occur and thus a frequent change of different sewing jobs takes place. Because under these circumstances the central creation of shirred values would be very cumbersome, only the usual one remains Approach that the operator on the sewing unit selects suitable shirring values. It follows from all of this that in general the sleeving procedures and sewing units do not Could contribute to the solution of the task according to the invention.

By developing the method according to claim 3, the Possibility opened, with a constant seam program any react finely to material-related differences in refinement to be able to z. B. in leather materials due to slight differences in thickness of the leather or other types of leather can.

In the other subclaims, advantageous developments of the Process or configurations of the sewing unit for carrying out the Procedure specified.

Fig. 1

eine schematisch dargestellte Nähmaschine und ein Blockschaltbild der Steuerungseinrichtung und

Fig. 2

eine schematische Darstellung des Haupt- und des Differentialtransporteurs.

The invention is explained with reference to an embodiment shown in the drawing. Show it:

Fig. 1

a schematically illustrated sewing machine and a block diagram of the control device and

Fig. 2

a schematic representation of the main and the differential feed dog.

From the sewing machine 1 are the main stitching device 2 and Differential stitch control device 3 shown, of which the first to Setting the basic stitch length on the main feed dog 4 (FIG. 2) and the second for setting the gathering value on the differential feed dog 5 serves. The differential stitch control device 3 is an actuator Stepper motor 6 assigned. Serves to drive the sewing machine 1 in known manner, a motor 7 with a controller 8, which with a Machine speed representative pulse generator 9 is connected.

Furthermore, a computer 10 is provided, which essentially consists of a Processor 11, an I / O element 12, an EPROM 13 and a RAM 14 consists. The computer 10 has a control panel 15, a knee switch 16 and the stepper motor 6 connected. The calculator 10 communicates with the engine control 8 via a bus 17 Starting and stopping the motor 7 or the sewing machine 1 serves a pedal 18. Finally, the computer 10 is also with if necessary an external PC 19 can be connected, the I / O element 12 being an interface forms. The sewing machine 1, the motor 7 with the motor control 8 and the computer 10 together with the control panel 15 form a sewing unit.

The mode of operation is as follows:

The operator takes the starting length l _{A of} a sewing material layer before gathering and the shorter target length l _s , which is to be achieved by gathering, from a work plan. It then communicates these values to the computer 10 via the control panel 15.

The computer 15 now calculates according to the formula MW = MW Max · l Max R Max - MW Max · L Max · L s R Max · L A the fullness MW in percent.

l_max =

100 %

R_max =

maximaler Raffwert in Prozent; z. B. 50 %, d. h. es kann in diesem Fall die Ausgangslänge auf den halben Wert gerafft bzw. vorgekräuselt werden, l_S = l_A · 0,5

MW_max =

100 %; d. h. die maximal erzielbare Mehrweite wird dann erzielt, wenn die Nähmaschine mit R_max arbeitet

Here mean:

l _max =

100%

R _max =

maximum gathering value in percent; z. B. 50%, ie in this case the starting length can be gathered or pre-crimped to half the value, l _S = l _A · 0.5

MW _max =

100%; ie the maximum achievable fullness is achieved when the sewing machine works with R _max

1. R_max = 50 %, l_A = 80 mm, l_s = 60 mm
MW = 100 . 100 / 50 - 100 . 100 . 60 / 50 . 80
MW = 50 %

2. R_max = 50 %, l_A · 80 mm, l_s = 75 mm
MW = 12,5 %

3. R_max = 50 %, l_A = 80 mm, l_s = 40 mm
MW = 100 %

The calculation is explained using a few examples:

1. R _max = 50%, l _A = 80 mm, l _s = 60 mm
MW = 100. 100/50 - 100. 100. 60/50. 80
MW = 50%

2. R _max = 50%, l _A · 80 mm, l _s = 75 mm
MW = 12.5%

3. R _max = 50%, l _A = 80 mm, l _s = 40 mm
MW = 100%

The computer 10 converts the calculated current fullness MW into corresponding step signals for the stepper motor 6, whereupon the latter adjusts the differential stitching device 3 to the current shirred value R _a corresponding to the current fullness. The sewing machine 1 can then be started by actuating the pedal 18. Because the differential feed dog 5 performs larger feed steps than the main feed dog 4, the sewing material layer is crimped by the amount of the gathering value with each common feed step of the two feed dogs 4, 5, whereupon this condition is fixed by the subsequent stitch formation.

The ruffling effect during gathering results in a build-up of material between the throat plate 20 and the presser foot 21 and, due to the resulting lifting of the presser foot 21, an increased braking effect of the presser foot 21 compared to the crimped material position. The consequence of this is that a slip occurs between the feeders 4, 5 and the sewing material layer, which is greater the greater the set shirring value. Because of the slip, the actual stitch length Stl _t , which is dependent on the gathering value, is obtained, which is significantly smaller than the set basic stitch length of the main conveyor 4.

The length of a fullness section can be determined by the operator by observing the seam course, by saving and later Calling up the number of stitches in a teach-in mode or by default or calculate the actually necessary or current number of stitches be determined.

For the calculation of the current number of stitches Stz _a , a table is stored in the EPROM 13, in which the value of the assigned actual stitch length Stl _{t is} entered for each adjustable gathering value, in which the slip-dependent slip of the conveyors 4, 5 is taken into account.

The current number of stitches Stz _a is then calculated in the computer 10 using the formula stz a = l s stl t where l _{s is} again the nominal length of the sewing material layer and Stl _{t is} the actual stitch length caused by slip, depending on the gathering value.

The computer 10 can now control the end point and thus the total length of a fullness section very precisely using the current number of stitches _a .

The values relating to the output length l _A and the target length l _s can also be set externally, e.g. B. the computer 10 via a PC 19.

When a seam is made up of at least one un-gathered smooth Seam section and at least one multi-width section, it may be appropriate for the formation of this seam record the required setting data in a program that is then stored in RAM 14. This is usually the beginning a multi-section by the operator by pressing of the knee switch 16 initiated during the end of the multi-width section - As explained above - by the computer 10 is controlled.

Such a program in the form of a u. Several different ones Comprehensive adjustment profile can be in any number definable intervals and thus in small or large steps in Towards a stronger or weaker refining intensity as a whole be moved. This way it can be very targeted material-related differences in refinement are reacted to. in this connection the accuracy and reproducibility is promoted in that the stepper motor 6 in terms of control in such a way to the control characteristic the differential stitch control device 3 was adapted that the Increments between two neighboring shirring value settings lead equidistant shirring results.

Claims (7)

1. Method of incorporating extra width in a sewing material ply by means of a sewing machine (1), having a principal and at least one differential transporter (4, 5), a principal and a differential stitch adjusting device (2, 3), an adjusting member (6) for adjusting the differential stitch adjusting device (3) and a computer (10) for controlling the sewing machine, characterised by the following steps:

   a) the starting length l_A of the sewing material ply is determined,

   b) the desired length l_S of the sewing material ply is determined,

   c) an actual gather value R_a is calculated from the starting length l_A, the desired length l_S and the maximum settable gather value R_max of the differential transporter (5),

   d) the differential stitch adjusting device (3) is set to the actual gather value R_a,

   e) an effective stitch length value Stl_t which takes account of the displacement of the transporters (4, 5), which displacement is dependent on the gather value, is read from a data storage unit (13) by means of the actual gather value R_a,

   f) the actual stitch number Stz_a is calculated from the desired length l_S and the effective stitch length value Stl_t, and

   g) the end point of an extra-width portion is determined by means of the actual stitch number.
2. Method according to the preamble of claim 1, characterised by the following steps:

   a) the starting length l_A of the sewing material ply is determined,

   b) the desired length l_S of the sewing material ply is determined,

   c) a preliminary gather value R_v is calculated from the starting length l_A, the desired length l_S and the maximum settable gather value R_max of the differential transporter (5),

   d) a correction value, which takes account of the displacement of the transporters (4, 5), which displacement is dependent on the level of the gather value, is read from a data storage unit (13) by means of the preliminary gather value R_v,

   e) the principal stitch adjusting device (2) is set, by using the correction value, to a corrected stitch length value which is greater than the basic stitch length value,

   f) the differential stitch adjusting device (3) is set, by using the correction value, to a corrected gather value R_k which is greater than the calculated preliminary gather value R_v,

   g) the actual stitch number Stz_a is calculated from the desired length l_S and the value of the basic stitch length, and

   h) the end point of an extra-width portion is determined by means of the actual stitch number.
3. Method according to claim 1 or 2, characterised in that a programmable and storable gather value setting profile is displaceable, in a plurality of optionally spaceable steps, in the direction of a stronger or weaker gather intensity.
4. Method according to claim 1, 2 or 3, characterised in that the values for the starting length l_A and the desired length l_S of the sewing material ply are communicated to the computer (10) via a control panel (15) and/or an interface (12).
5. Sewing unit for accomplishing the method according to claims 1 or 2, having the following features:

   a) a sewing machine (1) includes, inter alia,

   a principal and a differential transporter (4, 5),

   a principal and a differential stitch adjusting device (2, 3) and

   an adjusting member (6) for adjusting the differential stitch adjusting device (3),

   b) a computer (10) for controlling the sewing machine (1),

   c) an inputting device (12, 15) for the starting length l_A and the desired length l_S of the sewing material ply, and

   d) a data storage unit (13), in which are stored the effective stitch length values Stl_t which take account of the displacement of the transporters (4, 5), which displacement is dependent on the gather value.
6. Sewing unit according to claim 5, characterised in that the inputting device has a control panel (15) and/or an interface (12).
7. Sewing unit according to claim 6, characterised in that the adjusting behaviour of the adjusting member (6) is adaptable to the adjustment characteristic of the differential stitch adjusting device (5), to achieve equidistant gather value stages.

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