Abstract: A buttonhole forming apparatus includes a cutter, a cutter driving mechanism, and a needle plate. The needle plate has a needle plate base to hold a work cloth thereon and a pair of cutter guides in a recess to guide an edge of the cutter therein. The cutter guides are made of hard material on the inside and rubber on the outside. The hard material can be moved outward by the resilience of the rubber. The width of the cutter hole defined between the cutter guides is set as small as possible so that the cutter does not force the work cloth into the cutter hole when it is lowered where it remains clogged. When the cutter is gradually lowered, the edge of the cutter or a part of the work cloth to be cut makes contact with the tapered portions of the cutter guides, and the rubber is deformed to move the cutter guides outward.

Abstract: In a buttonhole sewing machine, a sewing mechanism and a feed bracket are controlled to form a buttonhole defined by settings, such as zigzag stitch length, zigzag pitch, bar-tack length, bar-tack pitch, and cutter space. The buttonhole can be set on the operation panel and changed to various shapes by changing the above settings. In particular, the left and right zigzag stitch widths can be set differently, and the front and rear bar-tack lengths can be also set differently. Thus, the balance of the buttonhole can be finely adjusted.

Abstract: A holing sewing machine including a workpiece-presser elevating and lowering mechanism which elevates and lowers a workpiece presser, a needle-thread cutting mechanism which cuts a needle thread conveyed by a sewing needle; a bobbin-thread cutting mechanism which draws a bobbin thread from a bobbin and cuts the bobbin thread, an interlocking mechanism which mechanically interlocks the elevating and lowering mechanism, the needle-thread cutting mechanism, and the bobbin-thread cutting mechanism, with one another, such that the elevating and lowering mechanism elevates the workpiece presser after the needle-thread cutting mechanism cuts the needle thread and the bobbin-thread cutting mechanism cuts the bobbin thread, a drive source which drives the interlocking mechanism to operate the workpiece-presser elevating and lowering mechanism, the needle-thread cutting mechanism, and the bobbin-thread cutting mechanism, the drive source being controllable with respect to a speed of operation thereof to drive the inter

Abstract: A fabric position correcting device detects the position of at least one of an outer profile line and a pattern of a fabric portion corresponding to one of pressers, corrects the position of the fabric portion while holding the same whose position has been detected, and presses the fabric portion with the presser after the position thereof has been corrected. The aligning process composed of the above three steps is carried out four times successively with respect to fabric portions corresponding to the respective pressers from the leading end of the fabric in the direction in which it is fed. Then, the positionally corrected fabrics are fed to the sewing start position. Therefore, the positional correction of the fabrics relative to at least one of the outer profile line and the pattern thereof can be accurately, reliably, and automatically carried out from the leading end to trailing end of the fabrics.

Abstract: A processing device for processing a sheet material with a pattern of the present invention is such as a sewing machine with pattern matching operation. The processing device has a detecting unit for detecting a color state of the pattern of the sheet material and producing a color state signal indicative of the color state. The processing device processes the sheet material on the basis of the color state signal produced by said detecting means. According to the present invention, the processing device is provided with an automatic adjusting unit for adjusting the detecting unit to allow the detecting unit to produce a desired color state signal with respect to a reference color state. Therefore, the white balance or the dynamic range is properly adjusted simply and reliably for the processing device.

Abstract: A fabric position correcting device for correcting relative position of two fabrics in terms of alignment in at least one of outer profile lines and patterns of the fabrics. A pair of fabric holders are provided which respectively hold first and second fabrics. The holders are movable in X, Y directions, and angularly rotatable about a vertical axis for moving the respective fabrics. A pair of image sensors are provided for picking up at least one of outer profiles and patterns of the respective fabrics. Data from the image sensors are utilized for computation of moving distance and angular rotation angle of the holders in order to eliminate misalignment between two fabrics in terms of at least one of the profiles and patterns.

Abstract: A pattern matching sewing machine comprises a sewing means for sewing two superposed sheets of cloth having substantially identical patterns thereon, a feeding means for feeding the two cloth sheets into the sewing means, a detecting means for detecting a mismatch distance between the patterns on the two cloth sheets, and a transport means to transport the two cloth sheets relatively. The pattern displacement amount detected by the pattern mismatch distance amount detecting means may be reduced. A determining means is provided for determining whether pattern matching is possible or not based on the information relating to the mismatch distance obtained by the detecting means.

Abstract: A pattern-matching joining machine for joining two sheets (e.g., sewing two cloths) having the same patterns with the patterns matching. The pattern-sensing photo-sensor generates intensity data for three different colors and the color data processed to correctly discriminate elements of a pattern having colors of similar brightnesses, and to accurately pick out pattern elements with faint colors from behind outstanding pattern elements. One way of processing the data includes calculating differences between intensity data for different colors. Another way includes selecting the color that has the largest intensity change.

Abstract: A pattern-matching sewing machine having a feed-correcting means for accurately adjusting feed amount using a correction factor with three values which are set according to various sewing conditions such as species of cloths and a speed of a main motor. When the feed amount for pattern matching is calculated based on only a mismatch distance detected by a photo-sensor, the accurate pattern matching is not achieved due to the various sewing conditions. Therefore, the feed-correcting means selects the optimum one of the three values to accurately correct the feed amount for a good pattern matching.

Abstract: A pattern-matching sewing machine for sewing two sheets, (e.g. two cloths) having the same patterns with their patterns matching. The sewing machine has a plurality of mismatch calculation modes. The operator selects one of the calculation modes appropriate to the type or characteristics of the pattern to be sewn and the mismatch distance is calculated according to the selected mode.

Abstract: A pattern-matching sewing machine that constantly samples photo-intensity data during calculation of a mismatch distance and during adjustment of the feeding mechanism based on the calculated mismatch distance. When the adjustment is finished, a new mismatch-distance calculation is quickly started, not by waiting for sampling new photo-intensity data of a predetermined number, but by using photo-intensity data of the predetermined number including the data thus sampled during the previous calculation and adjustment, and the previously stored data which have been used in the previous calculation.

Abstract: A sewing machine for sewing two overlapped cloth pieces including sensor means for detecting the intensity of light transmitted through each respective cloth piece, intensity curve generating means for generating respective intensity curves over a predetermined distance, differentiation means for differentiating between the intensity curves of each cloth piece and for generating differential curves for each cloth piece, difference determining means for determining a displacement between the two differential curves and feed pitch control means for adjusting a feed pitch based on the displacement. The sewing machine of the invention matches and sews the two cloth pieces having the same lateral and vertical patterns by ignoring the detected vertical pattern data having unclear and vague broad peaks and using the detected lateral pattern data having clear sharp peaks to have the two cloth pieces' patterns matched in alignment.

Abstract: Before sewing, a cloth pattern sensing means generates waveform signal corresponding to the overall width of two overlapping patterns corresponding to each other in two cloth pieces. The position difference between the patterns is calculated on the basis of the waveform signal. At least one of the feed pitches of the two cloth pieces is changed on the basis of data on the calculated amount of difference and data on the sensed cloth feed pitch. Data on the position difference amount between any patterns and the position difference amount between the next patterns are compared to calculate the direction in which the position difference amount increases or decreases, namely, the direction of the difference. Adjustment is made in the direction in which the amount of difference decreases on the basis of the result of calculation of the direction.

Abstract: A pattern sensor installed in a sewing machine for sensing patterns on two opposing sheets of cloth so that the patterns on the separate cloths are correctly aligned while sewing. The sensor is composed of a sensor head disposed between the two sheets of cloth, a light source, a light receiver, two light conduits including bundles of thin optical fibers, and a reflector which is composed of two prisms provided in the sensor head. The light emitted from the light source is transmitted via separate conduits and respectively enters the prisms. One beam is reflected upward toward the upper cloth, and the other is reflected downward toward the lower cloth for sensing the patterns. The light reflected on each cloth returns to the light receiver via the reverse route to be processed as a pattern signal.

Abstract: A pattern aligning device for a sewing machine having two two-dimensional pattern sensors, first and second computing means and first and second actuating mechanisms. Responsive to the two-dimensional pattern data sensed by the sensors, the first and second computing means compute the displacements between the patterns on the two sheets of material in two directions. The calculated displacements in the two directions are actuated by the first and the second actuating mechanisms to correct the alignment of the two sheets of material during sewing.

Abstract: The invention relates to a sewing machine provided with a needle reciprocated according to rotations of a main shaft and work feeding devices actuated synchronously with rotations of the main shaft, setting a margin to sew from a trailing edge to a sewing end position. The sewing machine includes devices for computing a terminal stitch length according to a set margin width. Control devices are provided for controlling a sewing to be carried out for coping with that which corresponds to the terminal stitch length computed by the computing device. The sewing machine further comprises computing devices for applying a correction to at least one of a number of stitches and a feed pitch, as occasion demands, where there arises the remainder as the result of an operation of the computing devices, and control devices for controlling the sewing to be carried out according to the computed result.

Abstract: Herein disclosed is a control unit for providing seam length control of a sewing machine which comprises: a main shaft; a sewing needle in accordance with the rotations of the main shaft for forming stitches in a work fabric which is placed on a work supporting surface so that it may be sewn; a feed dog for feeding the work fabric while passing a sewing point of the sewing needle; a work feed mechanism including a feed bar for carrying the feed dog and a feed shaft for supporting the feed carriage, the work feed mechanism being adapted to impart motions in a feeding direction to the feed dog by the reciprocating rotations of the feed shaft in accordance with the rotations of the main shaft; and mechanical adjusting means interposed between the work feed mechanism and the main shaft for adjusting a feed pitch of the feed dog by changing the reciprocating stroke of the feed shaft.

Abstract: A sewing machine has an automatic control system. This system provides for an automatic sewing mode for sewing according to previously stored sewing data and an ordinary sewing mode for sewing independently of the stored sewing data. When an interruption signal is generated by an interruption signal generating device during sewing process in the automatic sewing mode, the ordinary sewing mode is set and the pressure on the presser foot is released. Therefore, it is capable of smoothly feeding a material when feeding direction of the material is varied.

Abstract: A presser device for a sewing machine, comprising: pressing means reciprocally movable between a holding position in which it presses and holds a workpiece and a releasing position in which it is spaced the farthest from the workpiece; drive means for driving the pressing means; means for controlling the drive means so that the pressing means is brought into the holding means before the start of the sewing operation of the sewing machine; means for controlling the drive means so that the pressing means is brought from the holding position to the releasing position after the end of the sewing operation; timer means for setting a predetermined time from the instant when the pressing means is brought into the releasing position; and means for controlling the drive means so that the pressing means is brought from said releasing position to an optional intermediate position between the releasing position and the holding position after lapse of the predetermined time.