Workpiece cloth positioning guide device for sewing machine

Abstract

A workpiece cloth positioning guide device for a sewing machine includes a projector which projects a sewing reference mark onto an upper side of workpiece cloth placed on a sewing bed of the sewing machine. The projector projects light emitted from the light source onto a needle drop reference point of the sewing needle of the sewing machine from obliquely above so that a sewing reference mark including a circle having a center at the needle drop reference point on the upper side of the workpiece cloth and the sewing reference mark guides the workpiece cloth when the workpiece cloth is positioned in sewing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages of the present disclosure will become clear upon reviewing the following description of the illustrative examples with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a sewing machine in accordance with one illustrative example of the disclosure;

FIG. 2 is another perspective view of the sewing machine which is set with a workpiece cloth and from which a part of the head is eliminated;

FIG. 3 is a block diagram showing an electrical arrangement of the control system of the sewing machine;

FIG. 4 is a perspective view of a projector of the sewing machine;

FIG. 5 is a longitudinally sectional view of the projector;

FIG. 6 is a view taken along line VI-VI in FIG. 5;

FIG. 7 is a plan view of a sewing reference mark;

FIG. 8 shows a display screen displaying the contents of the sewing reference mark;

FIG. 9 shows another display screen displaying change of the color of the mark;

FIG. 10 is a top view of a part of the workpiece cloth in the case where the sewing reference mark is used in sewing;

FIG. 11 is a top view of the part of the workpiece cloth in the case where the sewing reference mark is used in sewing;

FIG. 12 is a top view of the part of the workpiece cloth in the case where the sewing reference mark is used in sewing;

FIG. 13 is a perspective view of the projector employed in the sewing machine of a second illustrative example in accordance with the present disclosure;

FIG. 14 is a block diagram showing an electrical arrangement of the control system of the sewing machine;

FIG. 15 shows a display screen displaying the contents of the sewing reference mark;

FIG. 16 is a perspective view of the projector employed in the sewing machine of a third illustrative example in accordance with the present disclosure;

FIG. 17 is a block diagram showing an electrical arrangement of the control system of the sewing machine;

FIG. 18 shows a display screen displaying the contents of the sewing reference mark;

FIG. 19 shows a display screen displaying change of the size of the mark;

FIG. 20 shows a part of an upper side of workpiece cloth with a presser foot being used in sewing in a conventional sewing machine; and

FIG. 21 shows a part of an upper side of workpiece cloth with a presser foot being used in sewing in another conventional sewing machine.

Claims

1. A workpiece cloth positioning guide device for a sewing machine which includes a sewing bed on which workpiece cloth to be sewn is placed, a light source and a sewing needle, the device comprising: a projector which projects a sewing reference mark onto an upper side of the workpiece cloth placed on the sewing bed of the sewing machine, wherein:the projector projects light emitted by the light source onto a needle drop reference point of the sewing needle of the sewing machine from obliquely above so that a sewing reference mark including a circle having a center thereof at the needle drop reference point on the upper side of the workpiece cloth; andthe sewing reference mark guides the workpiece cloth when the workpiece cloth is positioned in sewing.

2. The workpiece cloth positioning guide device according to claim 1, wherein the projector includes a mark size setting unit which is capable of setting a size of the circle of the sewing reference mark to a desired size.

3. The workpiece cloth positioning guide device according to claim 2, further comprising a mark size display unit which displays the size of the sewing reference mark set by the mark size setting unit.

4. The workpiece cloth positioning guide device according to claim 2, wherein the projector includes a telescopic cylindrical body having an upper end provided with the light source and a lower end, a transmission part provided in a lengthwise middle portion of the cylindrical body and formed with a mark forming pattern for forming the sewing reference mark, a projector lens provided in the lower end of the cylindrical body, and a projector lens elevating unit which raises and lowers the projector lens, and the mark size setting unit is capable of changing the size of the sewing reference mark by raising and/or lowering the projector lens by the projector lens elevating unit.

5. The workpiece cloth positioning guide device according to claim 4, wherein the mark size setting unit includes a mark size inputting unit which inputs the size of the sewing reference mark and an actuator which drives the projector lens elevating unit according to the size input by the mark size inputting unit.

6. The workpiece cloth positioning guide device according to claim 4, wherein the projector is set with a shape of the mark forming pattern or a predetermined position of the transmission part relative to the cylindrical body so that the circle of the sewing reference mark has a predetermined circularity.

7. The workpiece cloth positioning guide device according to claim 1, wherein the sewing reference mark includes a cross having an intersection at the needle drop point.

8. The workpiece cloth positioning guide device according to claim 1, further comprising a mark color changing unit which changes a color of the sewing reference mark to be projected by the projector to one of a plurality of colors.