US3830175A

US3830175A - Sewing machines

Info

Publication number: US3830175A
Application number: US00300182A
Authority: US
Inventors: H Levor
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-10-24
Filing date: 1972-10-24
Publication date: 1974-08-20
Anticipated expiration: 1991-08-20

Abstract

An improvement for sewing machines, whereby conventional sewing machines may be converted to perform specialized operations heretofore only achievable on special machines referred to as tackers. A clamp system clamps the fabric, with a two dimensional drive system advancing the fabric through a predetermined pattern so as to automatically sew button holes, pockets and the like. A sensor on the sewing machine synchronizes the fabric advance system with the sewing machine operation and advances the fabric in the inactive portion of the sewing cycle, so that sewing occurs in stationary rather than moving fabric. Provision is made for adjusting the pattern as desired.

Description

United States Patent Levor SEWING MACHINES [76] Inventor: Henry Levor, 12947 l-lisley St., Van Nuys, Calif. 91403 [22] Filed: Oct. 24, 1972 [21] Appl. No.: 300,182

[52] [1.8. CI. ll2/12l.12

[51] lnt. Cl D05b 21/00 [58] Field of Search 112/l21.12,121.15, 102, 112/203, 121.11; 192/489 [56] References Cited UNITED STATES PATENTS 2,557,967 6/1951 Hudson et a1 192/482 2,837,046 6/1958 Carson et a1 112/12l.12

3,001,489 9/1961 Bond et al. l12/l21.l2

3,072,081 1/1963 Milligan et a1. 112/121.12

3,224,393 12/1965 Adams et a1 112/102 3,385,245 5/1968 Ramsey et a1. 112/121.12

3,654,882 4/1972 Kamena 112/121.11

Primary Examiner-James R. Boler Assistant Examiner-Peter Nerbun Attorney, Agent, or FirmSpensley, Horn and Lubitz [5 7 ABSTRACT An improvement for sewing machines, whereby conventional sewing machines may be converted to perform specialized operations heretofore only achiev-' able on special machines referred to as tackers. A clamp system clamps the fabric, with a two dimensional drive system advancing the fabric through a predetermined pattern so as to automatically sew button holes, pockets and the like. A sensor on the sewing machine synchronizes the fabric advance system with the sewing machine operation and advances the fabric in the inactive portion of the sewing cycle, so

that sewing occurs in stationary rather than moving fabric. Provision is made for adjusting the pattern as desired.

14 Claims, 4 Drawing Figures PAIENIEU M2919 S'EET 1 (IF 2 SEWING MACHINES 1. Field of the Invention This invention relates to the field of sewing machines, and particularly industrial sewing machines for use in specialized operations, referred to in the industry as tackers.

2. Prior Art Both special purpose and general purpose sewing machines are well known in the prior art. General purpose sewing machines are machines characterized as being capable of basically straight stitching, with patterns and the like being creatable through the use of such machines by manually manipulating the material as desired to result in the desired stitching. Such machines may include adjustments for determining the length and other characteristics of the stitch, though all such machines are intended for manual guidance and manipulation of the material as well as manual control of the machine operation to achieve the desired end result.

Special purpose machines are generally machines for semi-automatically achieving the desired stitch without the attendant manual manipulation of the material. Certain machines of this type are referred to as tackers, which may be used to sew pockets, button holes and the like, merely. by placing the material at a predetermined starting position with respect to the needle and activating the sewing machine, whereby the machine will cause the material to generally advance through a predetermined path to create the stitch desired.

Prior art tackers as are commonly in use have certain undesirable characteristics. Since-they must not only sew, but trace out variable patterns depending upon some variable pattern determining means, such machines are generally more expensive than ordinary sewing machines and are limited to certain predetermined operations. They cannot be used for general sewing purposes. Consequently, such machines represent a substantial investment in equipment which is not of general use and can only be justified in those instances where a sufficient use of such machines can be made.

Also, in the prior art tackers, the means for determining the pattern to be sewn is comprised of a changeable cam system, generally located under the machine. Accordingly, a special cam, itself being relatively expensive, must be made for each different pattern to be sewn by the machine. Furthermore, the cam system is generally buried within the mechanical assemblage of the machine so that the changingof cams requires a substantial amount of time of a skilled mechanic, representing a substantial cost in the cam, mechanics time and the loss of use of the tacker while a change is being made.

Therefore it may be seen that prior art tackers require the careful attention of a skilled operator to achieve the desired result, are relatively expensive machines having a very limited use, require the fabrication of relatively expensive cams to be capable of sewing new patterns, and require considerable effort of a skilled mechanic to change cams to a new pattern. Accordingly, there is a need for a system whereby a function of a tacker may be achieved, preferably by an attachment to a conventional machine, whereby variations in the pattern sewn may readily be achieved by the operator as desired, where the fabric is firmly grasped so as to be caused to accurately move to traverse the predetermined pattern, and whereby the machine may be used for general sewing requirements when not in use as a tacker.

BRIEF SUMMARY OF THE INVENTION An improvement for sewing machines, whereby conventional sewing machines may be converted to perform specialized operations heretofore only achievable on special machines referred to as tackers. A clamp system clamps the fabric in functional disposition with respect to the needle of the sewing machine, with a two dimensional drive system advancing the fabric clamp and thereby the fabric through a predetermined pattern so as to automatically sew button holes, pockets and the like. The two dimensional drive system is actuated by means of a stepper motor operative when the needle is withdrawn from the material so as to incrementally step the fabric between stitching cycles, thereby allowing the fabric to remain stationary while each stitch is being made. For this purpose, a sensor is provided on the sewing machine to synchronize the fabric advance system with the sewing machine operation. The Sensor provides a signal to a logic system also controlled in part by a plurality of switches adjustable in location so as to readily provide adjustment of the patternto be sewn. The system is adapted for attachment to a standard sewing machine and may be quickly removed therefrom, so that the machine may be used for other purposes as desired.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a sewing machine incorporating the present invention thereon.

FIG. 2 is a top view of the apparatus of FIG. 1.

FIG. 3 is an end view of a fabric clamp.

FIG. 4 is a circuit diagram for the control system of the apparatus of the present invention.

DETAILED DESCRIPTION OF THE INVENTION First referring to FIG. 1, the perspective view of the present invention apparatus, as it mounts on a sewing machine, may be seen. The conventional sewing machine, typically an industrial machine 20, is provided with a conventional table 22 and driven through an appropriate drive motor 24 and belt 26, with a handwheel 28 on the upper shaft thereof. In normal operation, sewing machine 20 has a reciprocating needle 30 driven by the shaft coupled to hand-wheel 28, and the material being sewn is advanced in synchronism with the motion of the needle 30 by the cooperative action of an engaging member below the needle and facing upward, and a second member holding the fabric downward against the engaging member.

In accordance with the present invention, a fabric clamp, generally indicated by the numeral 32, is provided to clamp and advance the material with respect to the needle operation inthe desired manner. The fabric clamp 32, which is further illustrated in FIGS. 2 and 3, is provided with a base plate 34 and a top plate 36, hingedly affixed to the plate 34 by hinges 38. Both plates 34 and 36 are provided with an opening 40, generally of a shape and size slightly larger than the pattern to be sewn. In the particular embodiment shown, the fabric clamp 32 is adapted for ease of operation through a compressed air actuated cylinder assembly 42, which may be actuated by means of compressed air for automatic opening and closing of the fabric clamp. Typically, the cylinder 42 may be spring loaded to either position, with compressed air being used to drive the cylinder to the opposite position, thereby allowing firm clamping yet easy unclamping of the fabric by the operator. 5

Fabric clamp 32 is supported in part by a first horizontal bar 44, slideably engaging a lead screw follower 46. Attached to the bar 44 by a member 48 is a second horizontal, substantially orthogonal bar 50, which slideably engages a second block or lead screw follower 52.

Threadedly

engaging blocks

46 and 52 are lead screws 54 and 56 respectively. Lead screw 54 is rotationally supported by

members

58 and 60, so that rotation of lead screw 54 will cause the advance of member 46 and a corresponding advance of the fabric clamp 32 by the sliding of bar 50 in block 52. An electric clutch 62 is coupled to lead screw 54 and a shaft 64 driven by a right angle gear drive mechanism 66. Similarly, lead screw 56 is rotationally supported by members 68 and 70, so that rotation of a lead screw may cause the ad vance in the second direction of member 52, thereby advancing material clamp 32 in the corresponding direction by the sliding of bar 44 in block 46. A second electric clutch 72 couples lead screw 56 to shaft 74, passing through gear box 66 to a second gear box 76. The gear box 76 is driven by drive motor 78 and contains two readily changeable gears, one mounted to shaft 74 and one mounted to shaft 80 of the drive motor 78 so that the relationship between the rotation of the two lead screws and the rotation of the drive motor may be quickly and easily changed by changing these two gears. Preferably the gears may be molded nylon gears, with the gear housing comprising merely a cover to avoid contamination and insertion of the fabric or other foreign material into the gear region.

Now referring to FIG. 4, where a circuit diagram of the control circuitry of the present invention may be seen, the circuitry is adapted to operate the

clutches

62 and 72 and stepper motor 78 through an appropriate stepper motor-drive circuit of the type well known for such motors. In particular, clutch signals for operating the clutches are provided on

lines

100 and 102, and forward and reverse command signalsare provided on

lines

104 and 106. A 24-volt DC power supply 108 is used to control the circuitry through a switch 110, which also closes a relay, activating the sewing machine drive system (commercial sewing machines typically have a continuouslyv running motor with an electrically actuated clutch-brake so as to provide a very quick turn-on and turn-off capability. In such circumstances switch .110 would provide one control to the relay actuating the clutch-brake). Other inputs into the system include a pulse switch 112, which in the preferredembodiment is a reed switch activated by a permanent magnet on the hand-wheel of the sewing machine attached to the upper shaft of the sewing machine. Thus, switch 112 may be seen in FIG. 2, with the permanent magnet 114 fastened to the hand-wheel 28 to actuate the switch. The location of the switch 112 and permanent magnet 114 is chosen so that the switch is actuated during a portion of the rotation of hand-wheel 28 when the needle is in an upper position, that is, is withdrawn from the fabric being sewn. Switch 112 isa single pole double throw switch, having a normal position as shown in FIG. 4. There is also provided four switching means 116, 118, 120 and 122, which may alse be seen in FIG. 1. These switch means, in the preferred embodiment, are Hall effect devices actuated by appropriately disposed permanent magnets located on a permanent magnet assembly 124, supported by an extension of rod passing through the lead screw follower 52. Thus, the motion of the permanent magnet assembly 124' will follow the motion of the fabric clamp 32. The switching means, 116, 118 and 120 and 122 are adjustable disposed by means of thumb screws on

members

126 and 128 as shown, so as to be movable within the slots of those members to any desired position and for tightening thereat. Member 128 is supported on a pair of rods 130 from the platform of the sewing machine, with slide assemblies 132 and thumb screws 134 allowing the adjustment in the separation between

switches

120 and 122 from

switches

116 and 118. Further, if desired, the relative positions of the magnet assembly 124 may be made adjustable on rod 50. However, a fixed location for the magnet assembly as shown will detennine a fixed starting position of the fabric clamp 32 in one axis, which has certain advantages, in that an operator will learn to recognize the fixed starting position, regardless of the disposition of switches 116 through 122 determining the size and shape of the pattern to be sewn. There are also provided manually operated

switches

136, 138 and 140.

Switch 136 provides for the manual advance of the fab-- ric clamp along the predetermined path, switch 138 caused the automatic return of the fabric clamp to its original position, and switch 140, which is used only in the event of trouble, provides for the resetting of the various logic elements of the circuitry.

The circuit is comprised of various functional blocks, which cooperate to achieve the desired result. In particular, Capacitor C1, Resistor R1 and Potentiometer P1 together with Resistor R2 and unijunction transistor T1 provides a unijunction transistor oscillator having a time constant of approximately 5 milliseconds, adjustable through the Potentiometer P1. J-K Flip Flop F 1 has the J and K terminals as well as the reset terminal connected to line 150, which when the sewing machine is activated at the beginning of the sewing cycle is at the high state. Thus, the unijunction oscillator provides the clock input through Flip Flop F1 by operating the flip flop as a square wave generator. NAND gates N1 and N2 effectively invert the output of Flip-Flop F1, with the output of both NAND gates being switched to the high state for a short time upon the firing of unijunction T1 as a result of the coupling of one input of the NAND gates to the unijunction. Inverters I1 and I2 merely reinvert the signals to establish the desired logic characteristics.

NAND gates N3, N4, N5 and N6 operate at the gated oscillator providing a pulse train on line 104 controlled in frequency by the frequency of oscillation of the unijunction Tl oscillator, and gated by the signal applied thereto on line 152. A similar signal is provided on line 106 through an inverter I4 as a result of a similar connection of NAND gates N7, N8, N9 and-N10, with the gating signal being applied on line 154. The signals applied to

lines

152 and 154 are derived from the output of NAND gate N11, which is applied through NAND gate N12 and inverter I30 to line 152, and through inverter I31, NAND gate N13 and inverter I6 to line 154. It may be seen that because of the presence of inverter I31, logical states on

lines

152 and 154 are opposite states, provided NAND gates N12 and N13 are enabled by the output of NAND gate N14. Thus when the output of NAND gate N14 is in the proper logic state, it enables one of the gated oscillators, dependent upon the output of NAND gate N11, and will provide a forward stepping signal on line 104 to drive the stepper motor 78 in a first direction, or will provide a reversing signal on line 106 to drive the stepper motor 78 in a reverse direction in accordance with the output of NAND gate N11.

The combination of capacitor C2, resistors R3, R4 and R5 and unijunction T2 provides a second unijunction oscillator, with the value of C2 and R3 being selected to provide a time constant on the order of one second. This time constant is longer than the time required for the sewing machine to sew any specific pattern, so that by the time the unijunction transistor T2 fires the sewing has completed the full pattern. Thus, when unijunction transistor T2 fires, silicon controlled rectifier SCRl fires and latches, thereby applying a reset signal through inverter 17, NAND gate N15, inverter 18 to .l-K flip-flops F2 and F3, and through inverter [30 to a package of four clocked flip-flops F4. Thus, after the completion of the sewing of the desired pattern, the flip-flops F2, F3 and F4 are reset in readiness for the next sewing cycle (also the flip-flop comprised of NAND gates N61 and N62 to reset at this time).

When the next sewing cycle is initiated, switches 116, 118 and 120 will be in the open condition, so that the signals applied to the first three flip-flops of flip flop quad F4 through

inverters

19, 110 and Ill are in the low state, with the inverse outputs in the high state, initially put there with the reset signal and remaining there regardless of the occurrence of a clock signal because of the input states. Consequently, because of the combination of NAND gates N52, N53, N54 and N55 and N15, the output of NAND gate N54 will be in the high state, thereby disenabling the X-clutch 72. The output of the fourth flip-flop, when reset, will be in the low state. If switch 122 is closed in this condition, the input to this flip-flop will be in the low state, thereby commanding the output of the flip-flop to remain in the low state. Thus, even though the clock signal will be enabled through NAND gates N16 and N17 so that the output of inverter 11 in the reference oscillator will be applied through NAND gate N17 and inverter I12 to clock all four flip-flops F4, the outputs commanded will remain as reset. Thus, the output of the fourth flip-flop is in the low state, commanding the output of NAND gate N53 to be in the high state and accordingly the output of NAND gate N55 to be in the low state, thereby leaving the Y-Clutch 62 engaged.

As the pulse switch 112 senses the rotation of the hand-wheel, and particularly through a period during which time the needle is in the withdrawn or up position, the switch 112 will move to the lower position momentarily and then return to the upper position. This causes a set-reset cycle of the flip-flop comprising NAND gates N18 and N19, the cycle time of which is long compared to the sequence of switching occurrences about to be described, and long in comparison to the period of the clock signal originating from the unijunction transistor oscillator determining the clock signal for the system. When the switch 112 moves to the lower position, the output of NAND gate N19 is caused to be in the high state and therefore the output of NAND gate N18 to be in the low state. Thus, the inverse output of flip-flop F3 on line 160 enables the forward and reverse signals, ultimately appearing on

lines

104 and 106, through NAND gate N14.

NAND gate N30 and inverter I13 provide a clock signal to the flip-flop F5 responsive to either a forward or a reverse signal on

lines

104 and 106 to clock flip-flop F5. Consequently, after two pulses of either a forward or reverse signal, the inverse output of flip-flop F3 coupled to NAND gate N14 results in a disabling signal to NAND gates N12 and N13, thereby preventing any further forward or reverse signals to the stepper motor until switch 112 returns to its normal position and again is actuated. Thus, two step pulses are delivered to the stepper motor, either to step stepper motor 78 in the forward direction or to step the motor in the reverse direction.

When sewing proceeds to the limit of the Y direction travel, predetermined by the physical position of switch 116, that switch is closed, thereby providing a high state signal to the first of the flip-flops F4 and simultaneously enabling a clock signal, through NAND gate N16, from inverter 11 through NAND gate N17 and inverter 112 to the four flip flops F4. Consequently, the inverse output of the first flip-flop goes to the low state forcing the output of NAND gate N55 to the high state to disengage the Y clutch 62. At the same time, the input to the fourth flip-flop, being in the high state, (switch 122 is now open) causes the output of the fourth flip-flop to also go to the high state upon occurrence of the clock signal. Thus all inputs to NAND gate N54 are in the high state so that the output goes to the low state, thereby enabling the X-clutch 72. Also, when the output of the fourth flip-flop of F4 goes to the high state, the output of NAND gate N11 goes to the low state, thereby changing the drive from a forward drive to a reverse drive, so that sewing now proceeds in the minus X direction until switch 118 is actuated.

When switch 118 is actuated, it may be shown that state, resulting in the change in the forward and reverse signals so that sewing then proceeds along the plus X axis until the final off-switch 122 is actuated. Switch 122 is coupled to the main relay, turning off the sewing machine and further, is coupled to the NAND gate N61 which in combination with NAND gate N62 forms a bistable flip-flop, with the output thereof coupled to NAND gate N14 to. disable any further forward or reverse signals to the stepper motor until a new sewing cycle is actuated. It may be seen that once a sewing cycle is initiated, the sewing will proceed in a manner determined by the physical preadjustment of the

switches

116, 118, 120 and 122 with the sewing machine tuming off when the pattern has been completed. In addition, it should be noted that switch 122 is effectively a master off-switch for the system, so that that switch may be placed in the other positions within the switch pattern so as to automatically sew other shape patterns, such as U-patterns, L-patterns, etc.

There is also provided a switch 136 which provides an enabling signal to NAND gate N14 through the combination of inverter I20, flip-flop F2 and NAND gate N32. A reset cycle is provided to flip-flop F2, thereby disabling NAND gate N14, through the combination of inverter l2l, NAND gate N33 and Inverter I22, which receive their actuating signal in part from the output of NAND gate N16. Thus, enabling of the stepper motor is accomplished by pressing switch 136, with the stepper motor subsequently being disabled by the actuation of any of

switches

116, 118, 120 and 122. Thus, switch 136 manually accomplishes the stepping of the fabric clamp along any one axis of the predeter mined pattern without sewing during that progression. Switch 138, on the other hand, sets the flip-flop comprised of NAND gates N61 and N62, thereby coupling an enabling signal directly into NAND gate N14, allowing the fabric pattern to proceed along the predetermined path to the starting point without sewing. Thus, switch 136 accomplishes the automatic motion along any one axis of the pattern, whereas switch 138 will cause the motion from any fixed position back to the starting position.

The sewing time required to traverse a typical pattern is in the order of a fraction of a second. Thus, when the silicon controlled rectifier SCRl fires, the sewing cycle has been completed, and the result of this firing is to reset the flip-flops as hereinbefore mentioned (also resetting the flip-flop comprised of NAND gate N61 and N62, if switch 138 has been used). There is further provided a manual reset means by way of switch 140, which in general is only used when problems occur with the circuiter etc. (The remaining resistors, some of which are identified by the notation RB are bias resistors to determine the initial state of certain of the logic elements.)

In accordance with the foregoing description, it may be seen that two separate pulses are applied to the stepper motors on each stitch. Therefore to control the rate of fabric advance per stitch, changeable gears are provided on the shaft 80 of stepper motor 78 and on the extension of shaft 74 cooperatively disposed with respect thereto. Thus, variation of the stitch may readily be achieved by a quick and easy change of these gears. Also, it should be noted that the lead of the lead screws 54 and 56 is relatively high, so that a substantial advance may be achieved for each step of the lead screws depending upon the gears chosen.

There has been described herein an attachment for a conventional sewing machine which allows conventional tacking operations to be performed on such a machine. It should be noted that the apparatus of the present invention is primarily a bolt-on attachment to such sewing machines, so that it may be readily removed in the event the sewing machine is desired for ordinary duties. Thus commitment of a machine to use as a tacker is not required, and great versatility and minimum equipment cost is achieved. Also, it should be noted that by use of the stepper motor and lead screws as opposed to other driving means, the fabric may be stepped or advanced when the needle is withdrawn from the fabric, with the fabric remaining stationary during the time the needle passes through the fabric. Thus, elongation of the needle hole, dragging of the fabric, etc., is not encountered by use of the stepper motor, whereas a steady motion may cause such probpatterns. However, in the preferred embodiment a single stepper motor and two clutches are used because of the reduced cost of such a system. Of course, other lems, particularly with some materials. It is of course obvious that a separate stepper motor might be used for each axis, and in fact might be cooperatively controlled for the sewing of angles and other more complicated drive means may be used in place of the lead screws. Also while the specific system described herein has been described with respect to the generation of square and rectangular sewing patterns or portions thereof, of adjustable size and shape, both clutches might be simultaneously engaged during a portion of a sewing" pattern to sew angles. Similarly, obvious modifications in the system may be made so that the device would automatically electronically follow a pattern defined by various means such as a member bent in the appropriate shape and followed by a system of contact or proximity switches to control the X and Y clutches and the stepper motor to sweep out the pattern. Further, of course, a memory unit might be used to store the clutch and stepper motor command signals to cause the sewing of any predescribed pattern set in the memory unit. Such memory units are of course known in the prior art, and may be, by way of example, a semi-conductor memory device of the type manufactured by Intel Corporation, of Mountain View, Calif. These and other changes may readily be made by one skilled in the art to achieve substantially any sewing pattern and characteristics that may be desired, the preferred embodiment described herein being particularly desirable for most applications because of the ease in adjustment (programming) and relatively low cost and versatility thereof. Thus, while a preferred embodiment of the present invention has been described herein, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention.

I claim:

1. An improvement for sewing machines comprising:

a fabric support means for supporting fabric to be sewn in cooperative disposition with respect to the needle of a sewing machine;

a drive means and first and second lead screw means coupled to said drive means for advancing first and second members in first and second substantially orthogonal directions respectively in response to said drive means, said first and second members slideably engaging said fabric support means whereby said fabric support means follows said first member in said first direction and said second member in said second direction,

a right angle drive assembly and first and second electrically controlled clutches, said right angle drive assembly having a first input shaft coupled to said drive means, a first output shaft coupled to said first lead screw means through said first clutch, and a second output shaft substantially orthogonal to said first output shaft and coupled to said second lead screw means through said second clutch.

2. The improvement of claim 1 wherein said drive means is a stepper motor, said motor being coupled to said input shaft through a changeable gear ratio.

3. An improvement for sewing machines comprising:

drive means for advancing said fabric support means in first and second directions in response to drive means control signals, said drive means including at least one stepper motor;

a plurality of switch means cooperatively disposed with respect to said fabric support means including means to cause each of said switch means to be operable when said fabric support means and the respective one of said switch means are in a predetermined relative disposition, each of said switch means being adjustable in physical location in a plane so as to each define a location of a sewing pattern change on a desired two dimensional sewing pattern;

sensing means coupled to the sewing machine to provide a signal response to the passing of the sewing machine needle drive shaft through a predetermined angular position;

electronic means coupled to said switch means, said sensing means and said drive means, said electronic means being a means for generating a series of pulses in response to the output of said sensing means, to step said stepper motor a predetermined number of times, said electronic means further being a means for providing signals to said drive means responsive to said plurality of switch means to control the direction of stepping of said stepper motor and the selection of said first and second directions for advancement of said fabric support means.

4. The improvement of claim 3 wherein said drive means comprises:

first and second lead screw means coupled to said stepper motor for advancing first and second members in first and second substantially orthogonal directions respectively in response to said stepper motor, said first and second members slideably engaging said fabric support means whereby said fabric support means follows said first member in said first direction and said second member in said second direction.

5. The improvement of claim 4 wherein said fabric support means has a first and second substantially orthogonal bars coupled thereto, said first and second bars slideably engaging said first and second members respectively.

6. The improvement of claim 4 further comprised of a right angle drive assembly and first and second electrically controlled clutches, said right angle drive assembly having a first input shaft coupled to said stepper motor, a first output shaft coupled to said first lead screw means through said first clutch, and a second output shaft substantially orthogonal to said first output shaft and coupled to said second lead screw means through said second clutch.

7. The improvement of claim 6 wherein said stepper I motor is coupled to said input shaft through a changeable gear ratio.

8. The improvement of claim 3 further comprised of an advance switch, said advance switch being coupled to said electronic means, said electronic means further being a means for causing the advance of said fabric support means in the next one of said first and second directions upon actuation of said advance switch.

9. The improvement of claim 3 further comprised of a return switch, said return switch being coupled to said electronic means, said electronic means further being a means or causing the return of said fabric support means to a predetennined starting position upon actuation of said return switch.

10. An improvement for sewing machines comprising:

a plurality of switch means cooperatively disposed with respect to said fabric support means so as to be operable thereby, said switch means being adjustable in physical location so as to define points of sewing pattern change for a desired sewing pattern;

sensing means to sense the passing of the sewing machine needle drive shaft through a predetermined angular position and to provide a signal in response thereto;

electronic means coupled to said switch means, said sensing means and said drive means, said electronic means being a means for generating a series of pulses in response to the output of said sensing means, to step said stepper motor a predetermined number of times, said electronic means further being a means for providing signals to said drive means responsive to said plurality of switch means to control the direction of stepping of said stepper motor and the selection of said first and second directions for advancement of said fabric support means;

first and second lead screw means coupled to said stepper motor for advancing first and second members in first and second substantially orthogonal directions respectively in response to said stepper motor, said first and second members slideably engaging said fabric support means whereby said fabric support means follows said first member in said first direction and said second member in said second direction;

electrically controlled clutches, said right angle drive assembly having a first input shaft coupled to said stepper motor, a first output shaft coupled to said first lead screw means through said first clutch, and a second output shaft substantially orthogonal to said first output shaft and coupled to said second lead screw means through said second clutch.

11. The improvement of claim 10 wherein said stepper motor is coupled to said input shaft through a changeable gear ratio.

12. An improvement for sewing machines comprising:

a plurality of switch means cooperatively disposed with respect to said fabric support means including means to cause each of said switch means to be operable, said switch means being adjustable in physirightangle drive assembly and first and second cal location in a plane so as to define points of sewing pattern change for a desired sewing pattern;

an advance switch, said advance switch being coupled to said electronic means, said electronic means further being a means for causing the advance of said fabric support means in the next one of said first and second directions upon actuation of said advance switch.

13. The improvement of claim 12 further comprised of a return switch, said return switch being coupled to said electronic means, said electronic means further being a means for causing the return of said fabric support means to a predetermined starting position upon actuation of said return switch.

14. An improvement for sewing machines comprisa fabric support means for supporting fabric to be sewn in cooperative disposition with respect to the needle of a sewing machine;

drive means for advancing said fabric support means sensing means coupled to said sewing machine for providing a signal responsive to the passing of the sewing machine needle drive shaft through a predetermined angular position;

electronic means coupled to said switch means, said I sensing means and said drive means, said electronic means being a means for advancing said drive means in response to said signal from said sensing means and in a direction determined by the last of said switch means to be activated.

Claims

1. An improvement for sewing machines comprising: a fabric support means for supporting fabric to be sewn in cooperative disposition with respect to the needle of a sewing machine; a drive means and first and second lead screw means coupled to said drive means for advancing first and second members in first and second substantially orthogonal directions respectively in response tO said drive means, said first and second members slideably engaging said fabric support means whereby said fabric support means follows said first member in said first direction and said second member in said second direction, a right angle drive assembly and first and second electrically controlled clutches, said right angle drive assembly having a first input shaft coupled to said drive means, a first output shaft coupled to said first lead screw means through said first clutch, and a second output shaft substantially orthogonal to said first output shaft and coupled to said second lead screw means through said second clutch.

3. An improvement for sewing machines comprising: a fabric support means for supporting fabric to be sewn in cooperative disposition with respect to the needle of a sewing machine; drive means for advancing said fabric support means in first and second directions in response to drive means control signals, said drive means including at least one stepper motor; a plurality of switch means cooperatively disposed with respect to said fabric support means including means to cause each of said switch means to be operable when said fabric support means and the respective one of said switch means are in a predetermined relative disposition, each of said switch means being adjustable in physical location in a plane so as to each define a location of a sewing pattern change on a desired two dimensional sewing pattern; sensing means coupled to the sewing machine to provide a signal response to the passing of the sewing machine needle drive shaft through a predetermined angular position; electronic means coupled to said switch means, said sensing means and said drive means, said electronic means being a means for generating a series of pulses in response to the output of said sensing means, to step said stepper motor a predetermined number of times, said electronic means further being a means for providing signals to said drive means responsive to said plurality of switch means to control the direction of stepping of said stepper motor and the selection of said first and second directions for advancement of said fabric support means.

4. The improvement of claim 3 wherein said drive means comprises: first and second lead screw means coupled to said stepper motor for advancing first and second members in first and second substantially orthogonal directions respectively in response to said stepper motor, said first and second members slideably engaging said fabric support means whereby said fabric support means follows said first member in said first direction and said second member in said second direction.

7. The improvement of claim 6 wherein said stepper motor is coupled to said input shaft through a changeable gear ratio.

9. The improvement of claim 3 further comprised of a return switch, said return switch being coupled to said electronic means, said electronic means further being a means or causing the return of said fabric support means to a predetermined starting position upon actuation of said return switch.

10. An improvement for sewing machines comprising: a fabric support means for supporting fabric to be sewn in cooperative disposition with respect to the needle of a sewing machine; drive means for advancing said fabric support means in first and second directions in response to drive means control signals, said drive means including at least one stepper motor; a plurality of switch means cooperatively disposed with respect to said fabric support means so as to be operable thereby, said switch means being adjustable in physical location so as to define points of sewing pattern change for a desired sewing pattern; sensing means to sense the passing of the sewing machine needle drive shaft through a predetermined angular position and to provide a signal in response thereto; electronic means coupled to said switch means, said sensing means and said drive means, said electronic means being a means for generating a series of pulses in response to the output of said sensing means, to step said stepper motor a predetermined number of times, said electronic means further being a means for providing signals to said drive means responsive to said plurality of switch means to control the direction of stepping of said stepper motor and the selection of said first and second directions for advancement of said fabric support means; first and second lead screw means coupled to said stepper motor for advancing first and second members in first and second substantially orthogonal directions respectively in response to said stepper motor, said first and second members slideably engaging said fabric support means whereby said fabric support means follows said first member in said first direction and said second member in said second direction; a right angle drive assembly and first and second electrically controlled clutches, said right angle drive assembly having a first input shaft coupled to said stepper motor, a first output shaft coupled to said first lead screw means through said first clutch, and a second output shaft substantially orthogonal to said first output shaft and coupled to said second lead screw means through said second clutch.

12. An improvement for sewing machines comprising: a fabric support means for supporting fabric to be sewn in cooperative disposition with respect to the needle of a sewing machine; drive means for advancing said fabric support means in first and second directions in response to drive means control signals, said drive means including at least one stepper motor; a plurality of switch means cooperatively disposed with respect to said fabric support means including means to cause each of said switch means to be operable, said switch means being adjustable in physical location in a plane so as to define points of sewing pattern change for a desired sewing pattern; sensing means to sense the passing of the sewing machine needle drive shaft through a predetermined angular position and to provide a signal in response thereto; electronic means coupled to said switch means, said sensing means and said drive means, said electronic means being a means for generating a series of pulses in response to the output of said sensing means, to step said stepper motor a predetermined number of times, said electronic means further being a means for providing signals to said drive means responsive to said plurality of switch means to control the direction of stepping of said stepper motor and the selection of said first and second directions for advancement of said fabric support means; an advance switch, said advance switch being coupled To said electronic means, said electronic means further being a means for causing the advance of said fabric support means in the next one of said first and second directions upon actuation of said advance switch.

14. An improvement for sewing machines comprising: a fabric support means for supporting fabric to be sewn in cooperative disposition with respect to the needle of a sewing machine; drive means for advancing said fabric support means in first and second directions in response to drive means control signals, a plurality of switch means cooperatively disposed with respect to said fabric support means, said fabric support means including means for actuating each of said switch means when said fabric support means and the respective one of said switch means are in a predetermined relative disposition, each of said switch means further being adjustable in position in a plane so as to define points of sewing pattern change for a desired two dimensional sewing pattern; sensing means coupled to said sewing machine for providing a signal responsive to the passing of the sewing machine needle drive shaft through a predetermined angular position; electronic means coupled to said switch means, said sensing means and said drive means, said electronic means being a means for advancing said drive means in response to said signal from said sensing means and in a direction determined by the last of said switch means to be activated.