GB2116750A - Method for controlling an embroidery, stitching or sewing machine - Google Patents

Abstract

An embroidery, stitching or sewing machine comprises at least one needle and a jump stitch device which interrupts the penetration of the needle into the material being worked while the needle drive continues to operate and the material being worked is simultaneously conveyed over the length of the jump stitch. In order to markedly shorten the time necessary for executing jump stitches, the conveying movement of the material for one jump stitch, consisting of several fractional portions of the jump stitch, is executed in one operation 9 without any stoppage between the individual jump stitch fractional portions 8. Figures 1-3 show the prior art method and Figures 4-5 show the method of the present invention. <IMAGE>

Description

SPECIFICATION Method for controlling an embroidery, stitching or sewing machine The invention relates to a method for controlling an embroidery, stitching or sewing machine comprising at least one needle and a jump stitch device, which interrupts the penetration of the needle into the material being worked while the needle drive continues to operate and the material being worked is simultaneously conveyed over the length of the jump stitch.

In embroidery, stitching or sewing machines provided with a jump stitch device, it is known to interrupt the movement of the needle while the needle drive continues to operate, when particularly long stitches are to be executed. Such long stitches are not only necessary when extremely large distances between the last penetration and the subsequent penetration must be overcome during transfer to a new motif or when changing the thread, for example in order to take off the lastly used thread, but also in the case of embroidery, stitching or sewing operations requiring a stitch length which exceeds the normal stitch length dimension, and thus must be executed during more than one revolution of the needle drive.Atypical use of jump stitches arises for example when in an embroidery pattern a large area has to be executed with stitches which lie parallel to each other and which each have a length which exceeds the maximum possible stitch length.

In known jump stitch devices, the needle shank is uncoupled from the needle shank drive for this purpose, and is fixed at the top dead centre of the needle shank movement path. The material being worked is conveyed in single steps which correspond to the maximum stitch length of a normal stitch, namely during that time fraction of one revolution of the needle shank drive which is scheduled for conveying the material.

The drawback of this known jump stitch device is that time fractions between the individual portions of the jump stitch must be kept free for inserting the needle into the material being worked, even though the needle which has been uncoupled from the needle shank drive is fixed at the top dead centre of its movement and does not penetrate into the material to be worked. Because of this, the jump stitch devices require a relatively long time for executing the jump stitches.

The object of the invention is to provide a method for controlling an embroidery, stitching or sewing machine comprising a jump stitch device of the initially described type, by means of which the necessary time for executing embroidery, stitching or sewing work comprising jump stitches can be markedly shortened.

This object is attained according to the invention in that the conveying movement of the material for one jump stitch, and consisting of several fractional portions of the jump stitch, is executed in one operation without any stoppage between the individual jump stitch fractional portions.

In this manner, the control method according to the invention shortens the actual jump stitch operation substantially to the time necessary for conveying the material, this being independent of the time fractions which in normal embroidery, stitching or sewing operations are scheduled for the conveying of the material during the course of one revolution of the drive shaft.Whereas in the case of previous jump stitch operations, that time fraction of one revolution of the needle drive scheduled for the insertion of the needle into the material being worked is not used for conveying the material, even though the needle is not inserted into the material on account of the jump stitch, in the case of the control method according to the invention this time fraction of one revolution which is excluded from the conveying of the material is used to execute the jump stitch fractional portions which form one jump stitch without any intermediate stoppage times, consequently considerably shortening the time for the jump stitch operation.By virtue of this shortening, it is not only noticeable that there are no more stoppage times between the individual jump stitch fractional portions, but in addition the acceleration and deceleration stages between the individual fractional portions of the jump stitch are also eliminated, by virtue of which further considerable time saving is attained within one jump stitch operation.

These advantages according to the invention are attained both in the case of jump stitch devices with needle shanks which can be uncoupled from the needle shank drive and fixed in their upper end position, but also in the case of those constructions in which the stroke of the needle when executing a jump stitch is so displaced that the needle no longer becomes inserted into the material being worked.

In a preferred development of the control method according to the invention, the length data relative to the individual jump stitch fractional portions pertaining to one jump stitch and deriving from the data carrier for the embroidery, stitching or sewing programme, are added together in an adder element and are fed in the form of an item of total path data to the material movement drives, and, during the execution of the material movement for the total jump stitch, the respective residual path of the material movement which has still to be executed is determined, and if itfalls below a given residual value a signal is emitted for transferring the needle from its inactive position into the operating process.

By means of this embodiment of the control method according to the invention, existing data carriers for embroidery, stitching or sewing programmes can also be executed by using the control method according to the invention on existing embroidery, stitching or sewing machines, if the electronic components of the machine control systems are equipped in accordance with the inventive proposal.

In a preferred embodiment of the control method according to the invention, a further improvement can be attained by continuously feeding the residual value, based on utilising for the residual movement of the material the time interval between the transfer of the needle into the operating process and the insertion of the needle into the material being worked, to a comparator element which, when the value of the reducing residual path attains the residual value, emits the signal for transferring the needle into the operating process. In such an embodiment according to the invention, even that time which extends between the renewed drive of a needle which has been made inactive in order to execute a jump stitch and the insertion of this needle into the material being worked is also fully utilised for the residual movement of the material.In this respect, the control method according to the invention indeed ensures that the material has reached its final position after termination of the jump stitch, before the needle is inserted into the material.

The control method according to the invention is described hereinafter with reference to a drawing. In the drawing: Figure 1 is a diagram which shows the needle movement and conveying of the material for a normal embroidery operation in the form of five individual stitches each of maximum stitch length, Figure 2 is a diagram corresponding to Figure 1, which shows the needle movement and conveying of the material in executing a jump stitch with a known jump stitch control method, where the jump stitch comprises five fractional jump stitch portions, Figure 3 is a diagram which shows the conveying pattern of the material in executing the jump stitch of Figure 2, Figure 4 is an illustration corresponding to Figure 2 which shows the needle movement and conveying of the material in executing the jump stitch of Figure 2 by the control method according to the invention.

Figure 5 is a diagram corresponding to Figure 3 showing the conveying pattern of the material for a jump stitch in accordance with Figure 4, and Figure 6 is a circuit diagram of one embodiment of the electronic components of the control method according to the invention.

In Figure 1, the sinusoidal curve 1 shows the pattern of movement of the point of an embroidery needle, namelyforfive equal movement cycles which are produced for example by means of an embroidery needle crank drive. When the sinusoidal curve 1 is located above the horizontal axis of the coordinate system, this means that the point of the needle is not inserted into the material being embroidered. In this region of the sinusoidal needle movement the material beng embroidered can accordingly be moved. Arrows are correspondingly indicated on the horizontal axis of the diagram in this first half of the needle movement, to symbolise the movement of the material.As in the case of the illustrated embodiment it is assumed that the needle which is driven with to-and-fro movement between an upper and a lower inversion point is disposed in a stationary position, whereas the material being embroidered is moved relative to the needle, the arrows which symbolise the material movement on the time axis of the diagram correspond to the respective displacement movement of the material being embroidered.

Figure 1 shows that in executing five individual stitches the maximum time available for the conveying of the material is utilised in each case. In this respect, consideration must be given to the fact that the needle point must have reliably left the material being embroidered before the material movement can begin. On the other hand, it must be ensured that the material movement has definitely terminated before the needle dips into the embroidered material at the position determined by the end point of the respective stitch.That portion of the needle movement during which the needle is located in the material is then used to make a connection between the upper thread led by the needle into the material, and a lower thread which is inserted by means of a gripper or shuttle into the loop of the upper thread formed on the lower side of the material, before this upper thread is pulled tautly in order to execute the subsequent stitch.

The reference numeral 2 indicates the respective entry of the needle point into the material. The reference numeral 3 indicates the respective needle exit. One respective needle movement cycle 4 illustrated by the sinusoidal curve 1 lies between successive needle exits. The time fraction 5 illustrated by means of an arrow represents that region of the needle movement in which a displacement of the material can take place. One respective normal stitch of maximum stitch length is executed in Figure 1 within these time fractions 5.

As for a given speed of needle movement only that portion of the movement cycle 4 defined by time fraction 5 is available for displacing the material, in the case of known embroidery, stitching and sewing machines, long stitches, i.e. those exceeding the maximum length of a single stitch, are executed with the aid of a so-called jump stitch device. These jump stitches are accordingly composed of individual fractional portions of a jump stitch, between which the needle does not penetrate into the material being embroidered, as shown in Figure 2.

In Figure 2, the needle movement for a known jump stitch control method is shown by means of a curve 7. The jump stitch, formed from five jump stitch fractional portions 6, is produced by fixing the needle in a top dead centre position after the needle exit 3 at the beginning of the first movement cycle 4 of Figure 2, this being done not only during the remaining time of the first movement cycle 4, but during the total time of the following three movement cycles.

In the known jump stitch control method, the conveying of the material for the individual jump stitch fractional portions 6 in accordance with the movement pattern of Figure 1 is carried out exclusively within that time fraction of a movement cycle 4which during the normal movement pattern for individual stitches is provided for the material movement as a consequence of the needle being located outside the material being embroidered.

Consequently, Figure 1 shows that the needle entry 2 is only made when the material conveying for the individual jump stitch fractional portion 6 plus the intermediate material conveying rest pauses have been carried out. The advantage of the jump stitch control method of Figure 2 is exclusively that a longer stitch consisting of five jump stitch fractional portions 6 can be executed without the needle being inserted into the material being embroidered between the beginning and the end of this jump stitch.

The time for executing the jump stitch in accordance with Figure 2 equals the time for executing five individual stitches, as can be seen by comparing Figurs 1 and 2.

In Figure 3 the speed of movement of the material being embroidered is plotted against time. The illustration shows that the total movement 8 of the material being embroidered for one fractional portion 6 of a jump stitch is composed of an acceleration portion 8a, a portion 8b of maximum displacement speed, and a deceleration portion 8c. The projection of all three portions 8a, 8b and 8c together on to the horizontal axis of the diagram conjointly symbolises the displacement of the material being embroidered for one fractional portion 6 of a jump stitch.

Figure 4 illustrates by means of a diagram the control method according to the invention for an embroidery, stitching or sewing machine, in the execution of one jump stitch. The length of the jump stitch is equal to that of the jump stitch of Figure 2.

In the control method according to the invention, the conveying of the material for the jump stitch, consisting of several jump stitch fractional portions 6, is executed in one operation without any stoppage between the individual jump stitch fractional portions 6. Figure 4 shows the movement of the material being embroidered, which is executed directly consecutive and without intermediate stoppage times, and which has been divided into individual arrows symbolising jump stitch fractional portions 6 only for clarity. As these arrows do not represent the length of the jump stitch fractional portion 6, but instead indicate the time necessary for the material movement corresponding to the jump stitch fractional portion 6, the lengths of the jump stitch fractional portions 6 in Figure 4 are shorter than the length of the arrows in Figure 2.This arises from the fact that decelerations and accelerations of the material being embroidered occur between the individual fractional portions of the jump stitch, so that the time for moving the material being embroidered through a distance corresponding to the length of the individual jump stitch fractional portions 6 is shorter in the case of the control method according to the invention than in the case of the state of the art according to Figure 2.

By virtue of the shortening of the total time, as attained by the invention, for moving the embroidered material through the sum of the jump stitch fractional portions 6, it is sufficient as shown in Figure 4 for the embroidery needle not to penetrate into the material being embroidered during only one movement cycle 4. This time is sufficient for the material being embroidered to be displaced in one operation through the total jump stitch consisting of five jump stitch fractional portions 6. The needle point can penetrate again into the material being embroidered as soon as the middle of the second movement cycle 4 is reached, as shown by the needle entry 2 in Figure 4. By this means, not only considerable time reductions are attained in executing jump stitch operations.In addition, machine stresses are reduced because in executing jump stitches there are no decelerations, stoppage times or accelerations of the material being embroidered between the individual jump stitch fractional portions 6.

Figure 5 shows the movement 9 of the material being embroidered in executing a jump stitch by the control method according to the invention, in order to clarify the aforegoing description. The diagram shows that for the total jump stitch consisting of five jump stitch fractional portions 6, only one acceleration portion 9a and one deceleration portion 9c are present, so that the total movement of the material being embroidered is covered at maximum displacement speed substantially by the portion 9b.

Figure 6 shows a block diagram of a control system consisting of electronic components, for an embroidery, stitching or sewing machine. The components comprise a known reading device 10 for a data support, on which the respective programme for the machine is stored. An adder element is connected to the output side of the reading device 10, and its output is connected to a memory 12. The output of the memory 12 is connected to a setable counter 13, of which the output values are fed to a comparator element 14. A set residual value generator 15 is associated with the comparator element 14.

The connection between the electronic components 10 to 13 is illustrated by lines and arrows, and embraces a pulse counter 16 with a pulse generator 17 which operates independently and at high frequency. In addition, an OR gate 18 and an AND gate 19 connected to the input side thereof are associated with the pulse counter 16 for its zero setting. Finally, a bistable flip-flop 20 is provided, which can set the pulse counter 16 likewise to zero by way of the OR gate 18.

Each time a new stitch arises in an embroidery, stitching or sewing machine, the data for the stitch are recalled by the macine, with the control system shown in Figure 6. This recall operation operates the bistable flip-flop 20. It starts the pulse counter 16 by way of the OR gate 18. The pulse counter receives its pulse 16 from the pulse generator 17. In the illustrated embodiment, a maximum of five timing pulses of high frequency are provided.

With the first pulse, the value of the next stitch is called from the data carrier by way of the reading device 10. If this is a normal stitch, its value is fed by way of the adder element 11 to the memory 12, and is memorised with the second pulse. The third pulse is fed to the AND gate 19, but remains inactive because the supplementary condition, namely the presence of a jump stitch, is not fulfilled in the case of a normal stitch.

With the fourth pulse, which is also fed to the machine, the values stored in the memory 12 for the stitch to be executed are fed to the machine and simultaneously to the setable counter 13. The value stored in the setable counter 13 is reduced to correspond to the path increments being worked off, by way of a data line 21 from the machine movement devices. During this, the memory 12 is erased by the fifth pulse, and the pulse counter 16 is set to zero by way of the bistable flip-flop 20 and the OR gate 18.

The aforesaid process is repeated for each subsequent normal stitch.

As soon as data arises in the data support to the effect that the next stitch is the jump stitch fractional portion 6 of a jump stitch, a signal is fed to the AND gate 19 from the reading device 10, this signal by way of the OR gate 18 setting the pulse counter 16 to zero independently of the bistable flip-flop 20, as soon as the third pulse arises in the AND gate 19.

The value of the jump stitch fractional portion 6 is fed to the memory 12 by way of the adder element 11,and is stored in the memory 12 with the second pulse. As the pulse counter 16 is immediately set again to zero with the third pulse by way of the AND gate 19 and the OR gate 18, the pulses 4 and 5 are suppressed, so that in this case the bistable flip-flop 20 is not set into operation. Consequently a new pulse 1 follows, which in the assumed case of a jump stitch calls up the values of the second jump stitch fractional portion 6 from the data support. The values of this second jump stitch fractional portion 6 are added in the adder element 11 to the data relating to the first jump stitch fractional portion 6, and located in the memory 12. With the second pulse, the sum of this addition is transferred into the memory 12.The old information in the memory 12 is surpassed thereby.

As the last jump stitch fractional portion 6 pertaining to one jump stitch contains no further special jump stitch identification characteristic, the third pulse does not set the pulse counter 16 to zero by way of the AND gate 19. The pulse counter 16 accordingly runs on, whereas the values of the jump stitch fractional portions 6 added together in the adder element 11 are stored in the memory 12. On the fourth pulse, this total jump stitch data is fed from the memory 12 on the one hand to the machine and on the other hand to the setable counter 13. With the fifth pulse, the memory 12 is erased, and the bistable flip-flop 20 is set, whereby the pulse counter 16 is set to zero.

The output value from the setable counter 13 thus corresponds to the total length of the jump stitch which is to be executed, and which is composed of several jump stitch fractional portions 6. Path increments are continuously deducted from this total value as soon as they have been executed by the material conveying drives. During this process, the value of the reducing residual path contained in the setable counter 13 is continuously fed to the comparator element 14, in which the set residual value 15 is permanently present. So long as the reducing output value of the setable counter 13 is greater than the set residual value 15, the jump stitch device is controlled so that the needle does not take part in the operating process.When the reducing value of the residual path contained in the setable counter 13 attains the set residual value 15, the control of the jump stitch device is terminated by the comparator element 14.

The value of the residual path which is still to be executed, and which is still stored in the setable counter 13, is small enough to be able to be executed within the time interval between the transfer of the needle into the operating process and the penetration of the needle into the material being worked. In this manner, it is ensured that the needle penetrates into the material being worked only when the remainder of the last jump stitch fractional portion 6 of the respective jump stitch has been executed, and the material is stationary.

The operational pattern illustrated in Figures 4 and 5 which executes arising jump stitches within the shortest possible time can consequently be attained by the control system illustrated in Figure 6, which represents one embodiment using known electronic components.

Claims (6)

1. A control method for an embroidery, stitching or sewing machine comprising at least one needle and a jump stitch device, which interrupts the penetration of the needle into the material being worked while the needle drive continues to operate and the material being worked is simultaneously conveyed over the length of the jump stitch, characterised in that the conveying movement of the material for one jump stitch, and consisting of several fractional portions (6) of the jump stitch, is executed in one operation without any stoppage between the individual jump stitch fractional portions (6).

2. A control method as claimed in claim 1, characterised in that the length data relative to the individual jump stitch fractional portions (6) pertaining to one jump stitch and deriving from the data carrier for the embroidery, stitching or sewing programme, are added together in an adder element (11) and are fed in the form of an item of total path data to the material movement drives, and in that during the execution of the material movement for the total jump stitch, the respective residual path of the material movement which has still to be executed is determined, and if it falls below a given residual value (15) a signal is emitted for transferring the needle from its inactive position into the operating process.

3. A control method as claimed in claims 1 and 2, characterised in that the residual value (15), based on utilising for the residual movement of the material the time interval between the transfer of the needle into the operating process and the insertion of the needle into the material being worked, is continuously fed to a comparator element (14), which when the value of the reducing residual path attains the residual value emits the signal for transferring the needle into the operating process.

4. A method of operating a sewing machine having a needle drive and fabric feed means in order to produce a jump stitch having a stitch length greater than a normal maximum stitch length comprising preventing the needle from penetrating the fabric whilst operating the fabric feed means continuously until the fabric has been fed a distance equivalent to the desired stitch length.

5. A control method for an embroidery, stitching or sewing machine substantially as herein described with reference to Figures 4 to 6 of the accompanying drawings.

6. An embroidery, stitching or sewing machine adapted to operate in accordance with the method as claimed in any one of the preceding claims.