Electronically Controlled Sewing Machine Arranged to Sew a Sequence of Stitch Patterns

This invention relates to sewing machines and, more particularly, to electronically controlled sewing machines.

Sewing machines employing sophisticated electronic technology for the storage and subsequent retrieval of stitch pattern information for a multiplicity of patterns have enjoyed great commercial success in recent years. One great advantage of the use of an electronically controlled sewing machine is in its simplicity of operation and control, as perceived by the user. With the recent availability of relatively low cost microcomputers, electronically controlled sewing machines incorporating such a device have greatly increased the versatility of control afforded to the sewing machine operator. One aspect of such control has been to allow the operator to program a sequence, or string, of selected stitch patterns which are then sewn in the order of their selection. However, a disadvantage to all of the known arrangements for effecting the pattern stringing function is that if the operator desires to replace a single entry in the string, the entire string must be reentered into the sewing machine. Additionally, the known pattern stringing systems only allow a programmed stitch pattern to be sewn, without allowing any alteration thereto.

It is therefore a primary object of the present invention to provide an improved electronically controlled sewing machine having an arrangement for sewing a sequence of stitch patterns.

It is a further object of the present invention to provide such a sewing machine wherein each entry within a string of stitch patterns to be sewn includes the pattern identity as well as selective pattern alteration functions associated therewith.

It is another object of this invention to provide such a sewing machine wherein a selected individual entry in the string may be replaced with another entry.

The foregoing and additional objects are attained in accordance with the principles of this invention by providing an electronically controlled multiple pattern sewing machine including a central control system having a memory storing stitch pattern information, pattern selection input means for transmitting to the central control system a pattern selection signal identifying a selected pattern to be sewn by the sewing machine, alteration function input means for transmitting to the central control system selected pattern alteration function commands associated with a selected pattern on an individual basis to cause the central control system to alter the stored stitch pattern information in accordance with the selected pattern alteration function commands so as to sew a selectively altered version of a selected pattern, and pattern string memory means for storing a sequence of entries each comprising a respective pattern selection signal and associated selected pattern alteration function commands.

In accordance with an aspect of this invention, the sewing machine further includes means for replacing a selected individual entry in the pattern string memory means with another such entry.

The foregoing will be more readily apparent upon reading the following description in conjunction with the drawings wherein:

FIG. 1 is a front elevational view of an illustrative sewing machine in which this invention may be incorporated;

FIG. 2 illustrates a general block diagram of a microcomputer based control system for the sewing machine of FIG. 1;

FIG. 3 illustrates a portion of the internal temporary memory of the microcomputer shown in FIG. 2 showing the arrangement of the pattern string memory; and

FIGS. 4, 5 and 6 are flowcharts of subroutines for operating the microcomputer of FIG. 2 in accordance with the principles of this invention.

Referring now to the drawings, wherein like elements in different figures thereof have the same reference character applied thereto, FIG. 1 shows a sewing machine designated generally by the reference numeral 10. The sewing machine 10 includes a work supporting bed 12, a standard 14, a bracket arm 16 and a sewing head 18. The sewing machine stitch forming instrumentalities include a needle 20 capable of being endwise reciprocated and laterally jogged to form zig zag stitches and a work feed dog (not shown) operating upwardly through slots formed in a throat plate on the bed 12 to transport the work across the bed 12 between needle penetrations. The pattern of stitches produced by operation of the sewing machine 10, i.e., the positional coordinates of each stitch penetration, may be influenced, for example, by data stored in a memory unit and extracted in timed relation with the operation of the sewing machine 10, as is well known in the art.

On the front panel of the sewing machine 10 there is provided an input means whereby the operator can effect control of the functions of the sewing machine 10. This input means includes switches and dials whereby the operator may select a pattern to be sewn by the sewing machine 10 as well as effecting modifications, or alterations, to the selected pattern. Pattern selection is effected illustratively through an array 22 of push-buttons switches 24, each of which corresponds to a pattern of stitches, the information for forming which is stored in the memory of the sewing machine 10. Associated with each of the push-buttons switches 24 is a pictorial representation of the pattern as it would be sewn by the sewing machine 10 upon actuation of that switch. The input means also includes a stitch width control (bight override) 26 and a stitch length control (feed override) 28. The controls 26 and 28 each includes a push-button switch which is operator actuated to effect the respective width or length modification and includes a rotary portion for setting the magnitude of the modification. There are also provided push-button switches 30, 32 and 34 for selecting large buttonhole, small buttonhole and round-end buttonhole patterns, respectively. A push-button switch 36 is provided for reverse sewing. Single pattern selection is effected via a switch 38. The mirror image of a pattern in the bight direction is selected via the switch 40 and the mirror image of the pattern in the feeding direction is selected via the switch 42. The switch 44 is utilized for doubling the length of a sewn pattern. Thus, there are illustratively five pattern alteration function commands which may be provided under operator control. These are bight override, feed override, bight mirror image, feed mirror image and double feed.

Indicating means for indicating to an operator the status of each of the various functions which may be selected is also provided on the front panel of the sewing machine 10. Illustratively, this takes the form of a plurality of light emitting diodes (LEDs) 46 each in close proximity to its respective input switch.

In accordance with the principles of this invention, three push-button switches are provided to effect operator control of the pattern stringing function. These three switches are the ENTER (ENT) push-button switch 48, the MEMORY RECALL (MRC) push-button switch 50 and the CLEAR (CLR) push-button switch 52. Of these three push-button switches 48, 50 and 52 only the ENT switch 48 and the MRC switch 50 have associated LEDs 46. Pattern stringing permits the sewing machine operator to select a series of patterns from the repertoire of available patterns, together with desired pattern modifiers, and to enter these selections into a pattern string memory within the machine for subsequent automatic sequenced recall. When the string so programmed is sewn, each selection is reproduced once (or more if multiply entered) in the order selected, and the string may be sewn repeatedly.

Allowable pattern alteration function commands (modifiers) are bight override, feed override, bight mirror, feed mirror and double feed. When override values are mechanically set, such as by the dials 26 and 28, and there is no independent memory for the override values so that the mechanical setting itself retains the override value, then the logic control of the overrides is limited to activating or deactivating them only as programmed for each individual pattern. On the other hand, when override values are retained in an independent memory separate from the operator control, such as described in U.S. Pat. No. 4,177,744, the override values for each of the patterns in the string may also be stored in the pattern string memory. The single pattern modifier operates normally, i.e., it calls for one repetition of the string. Storage in a string of certain patterns and functions is not permitted, such as buttonhole patterns, reverse and single pattern.

Actuation of the CLR push-button switch 52 is effective only if the MRC push-button switch 50 has previously been actuated. A single actuation of the CLR switch 52 signals the logic that the next entry is to replace a previous entry at the same place in the string. A second actuation of the CLR switch 52 causes the logic to erase the entire string.

Actuation of the ENT switch 48 causes the logic to store the indicated pattern and any modifiers then in effect. An entry will always be placed at the end of a string unless either the CLR switch 50 has just been actuated once or the alloted pattern string memory space is full. Actuation of the ENT switch 48 is ignored if the MRC switch 50 has been actuated after a pattern selection has been made or if a non-permitted pattern, such as the buttonhole, is active.

Actuation of the MRC switch 50 causes the logic to invoke the stored string in place of a normal pattern. The operator may confirm the sequence of patterns programmed by successively actuating the MRC switch 50. All panel indicators will then show the pattern and modifiers selected for the respective place in the string. Stepping through the string by successive actuations of the MRC switch 50 is also utilized when the operator desires to replace an individual entry in the string.

FIG. 2 shows a general block diagram of a microcomputer-based controller for an electronic stitch pattern sewing machine, which controller may be utilized to control the operation of the sewing machine 10 (FIG. 1) and which operates in accordance with the principles of this invention. Accordingly, the microcomputer 60 receives input signals from the input switches 62 indicative of the functions the sewing machine operator desires to be performed by the sewing machine 10. The input switches 62 may include the pattern selection switches 24 and 30-34 as well as the function switches 26, 28 and 36-52. The microcomputer 60 includes an internal central processor unit (CPU) 64 and a program and pattern ROM 66 the CPU 64 obtains from the ROM 66, in timed relation with the operation of the sewing machine 10, pattern data for controlling the bight actuator system 68 and the feed actuator system 70. The bight actuator system 68 and feed actuator system 70 are similar in construction and are adapted to convert a digital code word from the microcomputer 60 into a mechanical position which locates the sewing machine needle 20 in a conventional stitch forming instrumentality and provides a specific work feed for each needle penetration, respectively, as is well known in the art. The microcomputer 60 also provides signals to the LED drivers 72 to control the illumination of the LEDs 46 (FIG. 1) to indicate the function selected by the sewing machine operator. Illustratively, the microcomputer 60 is a type TMS 7040 Microcomputer manufactured by Texas Instruments wherein the CPU 64 provides addresses to the ROM 66 over the lines 74 and receives in return bytes of data and program over the lines 76.

In addition to the ROM 66, the microcomputer 60 also includes read/write memory and registers which the CPU 64 utilizes during execution of its internal program stored in the ROM 66. In accordance with the principles of this invention, a portion of this temporary memory is dedicated as a pattern string memory which is utilized for storing a sequence of entries each comprising a respective pattern selection signal and associated selected pattern alteration function commands. FIG. 3 illustrates the organization of this pattern string memory. As shown in FIG. 3, each entry in the pattern string memory includes two bytes of information. The first byte holds the selected pattern number and the second byte holds the function flags. As discussed above, there are five allowable pattern alteration function commands. Accordingly, five bits of the second byte of each entry correspond to these five functions. The pattern string memory includes a plurality of addressable memory locations arranged in a predetermined order. The address of the first byte of the first entry is designated STRBGN and the first byte of the last entry is designated STREND.

The APPENDIX to this specification illustrates program subroutines for operating the microcomputer 60 to respond to actuation of the ENT switch 48, the MRC switch 50 and the CLR switch 52, as discussed above. This program is written in assembly language for the TMS 7040 microcomputer, and is for a sewing machine having a specific pattern switch configuration slightly different from that illustrated in FIG. 1. However, the operation of the sewing machine 10 in accordance with the program in the APPENDIX is as described above. It is understood that the program listing in the APPENDIX is only a portion of the entire program stored in the ROM 66.

FIGS. 4, 5 and 6 are flowcharts of the subroutines set forth in the APPENDIX and will be described hereinafter. However, before proceeding with a discussion of those flowcharts, certain definitions of variables and registers utilized in the subroutines set forth in the APPENDIX will be given. The variable STRPTR is used as a pointer which is set by the program to point to a location within the pattern string memory. Typically, this pointer is incremented either in response to successive actuations of the MRC switch 50 or as sewing progresses through the string. The variable STRFIN is a pointer which identifies the next free place in the string, i.e., the location within the pattern string memory closest to the beginning thereof which is available to accept an entry. Thus, both STRPTR and STRFIN can have values between and including STRBGN and STREND. The register STRFLG contains the string flags and each bit position within the STRFLG register corresponds to a particular function. For example, there is an MRC flag bit position within the STRFLG register which is set to ONE whenever the MRC switch 50 is actuated. Also, there is a CLR flag bit position which is set to ONE when the CLR switch 52 has been actuated once.

Referring now to FIG. 4, shown therein is a flowchart for the subroutine when the ENT switch 48 has been actuated. The ENT switch 48 should be actuated after a desired pattern and its alteration function commands have been selected for entry into the string, either as the last entry in the string or as a replacement for a previous entry. The selection of a pattern clears all the flags so that the MRC flag bit within the STRFLG register should not be set. If it is set, this indicates an improper actuation of the ENT switch 48 and the subroutine returns to the main program. The subroutine then checks to see whether there is room in the string for an entry. If STRFIN is less than or equal to STREND, then there is room. If there is no room, the subroutine checks the CLR bit position in STRFLG to see if this entry is a replacement. If not, the LED associated with the ENT switch 48 is caused to blink to indicate that there is no room for an entry into the string. If the entry is appropriate, the MRC and ENT LEDs are turned off and if the entry is a replacement then the CLR flag bit position in STRFLG is reset. If the string isn't empty, which is the case if STRFIN does not equal STRBGN, then the replacement entry is placed in the string at the location designated by STRPTR. If the entry is not a replacement or if the string is empty and the entry is a replacement, then STRPTR is advanced to STRFIN and then STRFIN is incremented. The entry is then placed into the string at the location designated by STRPTR and the subroutine returns to the main program.

Referring now to FIG. 5, shown therein is a flowchart for the subroutine which responds to actuation of the MRC switch 50. First the CLR flag bit position in STRFLG is reset. If the string is empty, which is the case if STRFIN equals STRBGN, the LED 46 associated with the MRC switch 48 is caused to blink to indicate that the string is empty and the subroutine returns to the main program. If the string is not empty, the MRC flag bit position in STRFLG is checked to see if it has already been set. If the MRC flag has not been set, STRPTR is set to STRBGN. If the MRC flag has been set and some of the string has been sewn, then STRPTR is set to STRBGN. If none of the string has been sewn, STRPTR is incremented. If STRPTR reaches STRFIN, then it is reset back to STRBGN. Thus, repeated actuations of the MRC switch 50 cause the pointer to sequence through the string. In any event, the MRC flag bit position in STRFLG is set and the program sets up for whatever pattern in the string STRPTR is pointing to and the subroutine then returns to the main program.

Referring now to FIG. 6, shown therein is a flowchart for the subroutine which responds to actuations of the CLR switch 52. This switch should only be actuated sometime after the MRC switch 50 has been actuated. If not, then the subroutine returns to the main program. If the MRC flag bit position in STRFLG is set, the CLR flag bit position in STRFLG is checked to see if it is set. If not, it is set and the subroutine returns to the main program. If it had been set, STRPTR and STRFIN are both set to STRBGN. This clears the string. The sewing machine is then set to some arbitrary default pattern, for example straight stitch, and the LED associated with the MRC switch 50 is caused to blink. The subroutine then returns to the main program.

Accordingly, there has been disclosed an electronically controlled sewing machine arranged to sew a sequence of stitch patterns with selective alterations thereto and wherein individual patterns within the sequence may be replaced. It is understood that the above-described embodiment is merely illustrative of the application of the principles of this invention. Numerous other embodiments may be devised by those skilled in the art without departing from the spirit and scope of this invention, as defined by the appended claims. ##SPC1##