A METHOD OF SHEET SEWING AND AN APPARATUS THEREOF

Abstract: A method of sheet sewing is providing a nozzle member(36) having a nozzle(35) adjacent a sewing needle(6) at an upstream side in a moving direction(40) of a sheet(8) and impregnating the sheet(8) with lubricating fluid(11) by supplying the lubricating fluid(11) from the nozzle(35). Thereby, component yarns of the sheet(8) are prevented from being severed when the needle(6) pierces through the sheet(8) and your severances are minimized.

Description: This invention relates to a method of sheet sewing and an apparatus thereof. When sewing operation is carried out employing conventional sewing techniques, so-called yarn severances often occur such that component yarns of the cloth being sewn are severed by a needle in course of the up and down reciprocating movement of the needle. It is strongly desired that such yarn severance be prevented particularly where garments such as lingeries and blouses are being sewn. The object of the invention is to provide a sewing method and an apparatus thereof which prevent yarn severances in sheet such as cloth or the like being sewn. In accomplishing the above object, a method of sheet sewing in accordance with the invention comprises the steps of; providing a nozzle member having a nozzle adjacent a sewing needle at an upstream side in a moving direction of a sheet to be sewn; and impregnating the sheet with lubricating fluid by supplying the lubricating fluid from the nozzle. In a preferred embodiment, the method comprises the step of; impregnating the sheet with the lubricating fluid also from a nozzle provided above the sheet. In another preferred embodiment, the lubricating fluid is liquid. In still another preferred embodiment, the lubricating fluid is vapor. In accomplishing the above object, a sheet sewing apparatus in accordance with the invention comprises; flat plates on which a sheet to be sewn is placed, moving means for moving the sheet on the flat plates toward a predetermined moving direction, a sewing needle for sewing the sheet being moved on the flat plates by the moving means, a nozzle member having a nozzle opened onto an upper surface of the flat plates at the upstream side with respect to the sewing needle in the moving direction, and supplying means for supplying the lubricating fluid to the nozzle. In a preferred embodiments, the nozzle member comprises, a chamber with which the nozzle communicates, a restriction hole formed coaxially with the nozzle and communicating with the chamber, and a supplying hole formed at shifted position from the restriction hole: and the supply means for supplying the lubricating fluid comprises, pumping means for pumping air into the restriction hole, and a vessel for storing the lubricating fluid provided in connection with the supplying hole. In another preferred embodiment, the pumping means for pumping air comprises, a diaphragm for defining a pump chamber, a suction relief valve for leading air to the pump chamber, a discharge relief valve for leading air from the pump chamber to the restriction hole, and a driving means for reciprocatingly moving the diaphragm. In still another preferred embodiment, the driving means comprises, a permanent magnet fixed to the diaphragm, coils for magnetically attracting and repulsing the permanent magnet, and an AC supply for energizing the coils. According to the invention, lubricating liquid is supplied onto the sheet such as cloth or the like being sewn through a nozzle so that the sheet is impregnated with the lubricating fluid, the sheet being then sewn by the needle. The needle pierces through that portion of the sheet which is thus lubricated with the lubricating fluid, and thus (a) the sheet can have good flexibility or softness; (b) the coefficient of friction between the needle and the sheet is reduced; and (c) the needle is cooled down. Accordingly, the possibility of yarn severance by the needle is eliminated. According to the invention, the sheet such as cloth or the like to be sewn is wetted by the lubricating fluid so that the sheet has good flexibility or softness given to it and so that the friction between the needle and the sheet is minimized. In addition, the needle is cooled down by the fluid. Thus, component yarns of the sheet are prevented from being severed when the needle pierces through the sheet and yarn severances are minimized. These and other objects, features and advantages of the invention will become more apparent upon a reading of the following detailed specification and drawings, in which; FIG. 1 is a partial perspective view showing one embodiment of the invention: FIG. 2 is a perspective view showing the sewing machine in FIG.1; FIG. 3 is a partial perspective view of the sewing machine in which the cloth in FIG. 1 is omitted; FIG. 4 is a schematic representation showing an arrangement associated with a nozzle and FIG. 5 is a graph showing a comparison between the invention and the prior art in the number of yarn severance occurrences per 100 stitches. Referring now to the drawings, embodiments of the invention are described below. FIG. 1 is a partial view in perspective of a sewing machine 1 showing one embodiment of the invention, and FIG. 2 is a general view showing the sewing machine 1 in perspective. A bed 3 of the sewing machine 1 is disposed on a table 2. The bed 3 is provided with a throat plate 4. In a head portion 5 of the sewing machine 1 there is up and down movably disposed a sewing needle 6 by which a needle thread 7 is carried. A moving means 39(see Fig.4 mentioned below) is in touch with an under surface of a cloth 8 being sewn, and the cloth 8 is moved in the direction indicated by the arrow 40. Stitches 10 are formed into the cloth 8 according as the cloth 8 is moved. FIG. 3 is a perspective view of the sewing machine 1 in which the cloth 8 is not shown. According to the invention, a nozzle 35 for spraying upward a mist of water as a lubricating fluid is provided in the throat plate 4 at a location adjacent the needle 6. FIG. 4 is a schematic view showing an arrangement associated with the nozzle 35. The nozzle 35 is formed in a nozzle member 36. A restriction hole 13 which is formed coaxially with the nozzle 35 has a diameter smaller than that of the nozzle 35, into which restriction hole 13, is pumped air from a pipeline 27 by a diaphragm pump 28 through a pipeline 9. Water 11 in a vessel 30 is supplied by suction into a chamber 37 between the nozzle 35 and the restriction hole 13 from a pipeline 12 through a supplying hole 41. A surface of liquid in the vessel 30 is opened to atomosphere. The air from the pipeline 9 allows water 11 to be sucked into the chamber 37 through the pipeline 12 by a Venturi action of the restriction hole 13, so that the water is sprayed upward in the form of a mist through the nozzle 35. The mist of water 11 is supplied onto the cloth 8 for lubrication. Stitches are formed as the needle 6 pierces through the portion of the cloth 8 which is moistened with water 11. A reference number shown by 38 is a needle hole through which the needle passes during sewing operation. The pump 28 has a diaphragm 15 provided in a pump body 14, said diaphragm defining a pump chamber 16. In the pump chamber 16 there are provided a suction relief valve 17 for flowing air from pipeline 27 to the pump chamber 16 when the pump chamber 16 is magnified and a discharge relief valve 18 for discharging air from the pump chamber 16 to the pipeline 9 when the pump chamber 16 is reduced. A link 19 is connected to the diaphragm 15, said link 19 being pin-connected to a lever 20. The lever 20 is supported at one end by a pin 21 in position so that it is angularly displaceable about the pin 21. A permanent magnet fragment 22 is fixed to the other end of the lever 20. Coils 23, 24 are disposed correspondingly to the respective poles of the permanent magnet fragment 22. The coils 23, 24 are connected in parallel and are supplied with exciting current from an AC supply 25 through a current regulator 26. When the permanent magnet fragment 22 is attracted by the coil 23, the magnet 22 is in magnetic repulsion against the coil 24. Conversely, when the permanent magnet fragment 22 is attracted by the coil 24, the coil 23 is in magnetic repulsion against the magnet fragment 22. Thus, the permanent magnet fragment 22 reciprocatingly moves rightward and leftward in FIG. 4. Accordingly, the diaphragm 15 is reciprocatingly moved so that air from the pipeline 27 is sucked into the pump chamber 16 and the air in the pump chamber 16 is pumped into the nozzle 35 through the pipeline 9. Experiments with the sewing machine of the invention will now be explained. The machine was run on a 4500 rpm basis. A needle 6 of DB × 1 # 11 (in Japanese Industrial Standard) was used. For the cloth 8, a Tetoron(registered trademark) and cotton mixed woven broad cloth was used in two ply. With a cloth forwarding pitch of 2mm, and a water spray of 4.3 cc / min, the cloth 8 was sewn up over a length of 80 cm. The number of yarn severance occurrences for 100 stitches formed prior to the end of this sewing operation was measured and the measurements are shown in FIG. 5. Normally there is a temperature rise at the needle 6 because of friction between the needle 6 and the cloth 8, before the end of a sewing operation. In such condition, yarn severances are likely to occur. According to the experiments with the invention, the number of yarn severances per 100 stitches was only one. In contrast to this, the number of yarn severances observed with a conventional sewing machine was 42. It is apparent from this comparison that the method and the apparatus thereof the invention helps reduce remarkably yarn severances. For the lubricating fluid, water or alternatively silicone oil or other liquid may be used. Vapour such as steam or the like may also be used. In the foregoing embodiment, the nozzle 35 is provided in the throat plate 4. Alternatively, it may be provided in the bed 3 or at another location. For example, above the bed 3 and the throat plate 4, in which case the lubricating liquid may be supplied from above onto the cloth 8 for lubrication. The nozzle 35 may be provided in plurality so that the lubricating fluid is supplied not only when the cloth 8 is running straightforward in the direction 40, but also when it is turned reverse so that such fluid supply is made constantly at the upstream side of the sewing position of the needle 6. The method of this invention and the apparatus thereof can be practiced in conjunction with various types of sewing machines, such as single needle lockstitch machine, double row stitch machine, zigzag chain stitch machine, overlock machine, and the like. In the case where the cloth 8 is of thick gage, the arrangement of the invention may be modified so that lubricating liquid is supplied not only through the nozzle 35 provided below the cloth 8, but also from a nozzle provided above the cloth 8, whereby the thick cloth is sufficiently moistened before it is sewn up by the needle.

Claims: A method of sheet sewing characterized by the steps of ; providing a nozzle member(36) having a nozzle(35) adjacent a sewing needle(6) at an upstream side in a moving direction(40) of a sheet(8) to be sewn; and impregnating the sheet(8) with lubricating fluid(11) by supplying the lubricating fluid(11) from the nozzle(35). A method of sheet sewing as claimed in claim 1, wherein the method is characterized by the step of; impregnating the sheet(8) with the lubricating fluid(11) from a nozzle provided below the sheet and from a nozzle provided above the sheet (8). A method of sheet sewing as claimed in claim 1, wherein the lubricating fluid(11) is liquid. A method of sheet sewing as claimed in claim 1, wherein the lubricating fluid(11) is vapor. A sheet sewing apparatus chaacterized in that there are provided ; flat plates(3,4) on which a sheet(8) to be sewn is placed, moving means(39) for moving the sheet(8) on the flat plates(3,4) toward a predetermined moving direction(40), a sewing needle(6) for sewing the sheet(8) being moved on the flat plates(3,4) by the moving means(39), a nozzle member(36) having a nozzle(35) opened onto an upper surface of the flat plates(3,4) at the upstream side with respect to the sewing needle(6) in the moving direction(40), and supplying means(9,12,14 to 30) for supplying the lubricating fluid(11) to the nozzle(35). A sheet sewing apparatus as claimed in claim 5, wherein the nozzle member(36) is characterized in that there are provided, a chamber(37) with which the nozzle(35) communicates, a restriction hole(13) formed coaxially with the nozzle(35) and communicating with the chamber(37), and a supplying hole(41) formed at shifted position from the restriction hole(13); and the supply means(9,12,14 to 30) for supplying the lubricating fluid(11) comprises, pumping means(9,14 to 28) for pumping air into the restriction hole(13), and a vessel(30) for storing the lubricating fluid(11) provided in connection with the supplying hole(41). A sheet sewing apparatus as claimed in claim 6, wherein the pumping means(9,14 to 28) for pumping air is characterized in that there are provided, a diaphragm(15) for defining a pump chamber(16), a suction relief valve(17) for leading air to the pump chamber(16), a discharge relief valve(18) for leading air from the pump chamber(16) to the restriction hole(13), and a driving means(19 to 26) for reciprocatingly moving the diaphragm(15). A sheet sewing apparatus as claimed in claim 7, wherein the driving means(19 to 26) is characterized in that there are provided, a permanent magnet(22) fixed to the diaphragm(15), coils(23,24) for magnetically attracting and repulsing the permanent magnet(22), and an AC supply(25) for energizing the coils(23,24).

Inventors: SHIMIZU, HIROMITSU HIROSE MANUFACTURING CO. LTD.
Applicants: HIROSE MANUFACTURING COMPANY LIMITED
Application year: 1987
Main classification: D05B81
IPC codes: D05B71, D05B67