A precision-stitch sewing machine

Abstract

 A precision-stitch sewing machine for applying an edging (2) to an end (3) to be edged of a knitted item, a fabric or the like, particularly a garment, along a predetermined seam line, comprising a folding unit for encouraging the edging (2) to fold astride the end to be edged (2) upstream of a sewing region in which a needle (12) operates, with reference to the direction of advance of the edging (2), a support table (13) for supporting the folded edging (2), as well as an element (22) for guiding the edging (2), movable between an advanced position and a retracted position relative to the seam line (X-X).

Description

[0001] The present invention relates to a precision-stitch sewing machine for applying an edging to an end to be edged of a knitted item, a fabric or the like, particularly of a garment, along a predetermined seam line, of the type comprising: a folding unit for encouraging the edging to fold astride the end to be edged upstream of a sewing region with reference to the direction of advance of the edging, a support table for supporting the folded edging, an element for guiding the edging by resisting and bearing against the outer curved portion of the folded edging, a hooked element for engaging a first edge of the folded edging, and actuating means connected to the hooked element in order to move it towards and away from a moved-away position in order to retract the first edge from the seam line relative to the other edge.

[0002] Solely for the purpose of simplifying the explanation of the present invention, the following description will refer, in non-limiting manner, to a garment.

[0003] It is known that the finishing of the ends of a garment such as the neck and the cuffs of a sweater is generally carried out by a so-called edging operation put into effect by the application of a knitted or fabric edging or the like to the end to be finished.

[0004] The edging operation can be carried out with the use of knitting machines which permit excellent finishing of the ends to be edged. However, these machines have the disadvantage of requiring a long period of time for the application of each edging which makes their use economically viable only for more expensive garments.

[0005] The edging operation can also be carried out with the use of precision-stitch sewing machines which enable the edging to be applied quickly and cheaply to the end to be edged by passing the edging through a folding unit which encourages the edging to fold astride the end to be edged before the sewing takes place.

[0006] The finishing which can be achieved with the use of precision-stitch sewing machines of the type currently used, however, is less precise than the finishing which can be achieved with the use of knitting machines. Consequently, whereas precision-stitch sewing machines are almost always used for medium/low-cost garments, the supremacy of knitting machines is difficult to undermine for the edging of more expensive and higher-quality garments for which even minimal imperfections are unacceptable.

[0007] The imperfections which may be found in the finishing of the neck and cuffs of a garment and which are brought about by the execution of the edging operation with the use of a precision-stitch sewing machine are found in the initial or final parts of the stitching performed by the machine. These imperfections can be attributed to the fact that the edging operation has to be carried out in a manner such as to leave one of the two edges of the edging, generally that on the inside of the garment, unsewn for a short section of the initial or final portion of the seam. This in fact enables the subsequent manual operation to join together and sew the two opposite ends of the edging, enclosing the ends of the edging having both edges sewn inside the end having an edge which is not sewn, to be carried out quickly. To enable a portion of one of the two edges of the edging not to be sewn, precision-stitch sewing machines have a hooking element which engages an edge of the edging upstream of the sewing region. After the operation of a control means, generally with a pedal, by a user of the machine, this hooked element is movable towards and away from a position in which it is moved away from the seam line in order to retract the aforesaid edge of the edging from the seam line during its advance so that it is not sewn. The retraction of the aforesaid edge of the edging, however, causes the other edge to advance relative to the seam line so as to cause a visible and undesired slippage of the seam.

[0008] It is clear from the foregoing that there is a need for the edging operation on an end to be finished to be carried out more quickly and cheaply than can be achieved with knitting machines but without compromising the precision of the finishing achieved.

[0009] The problem upon which the present invention is based is that of devising a machine for carrying out the edging operation which has structural and functional characteristics such as to satisfy the aforesaid requirement and at the same time to solve the problems of the prior art referred to.

[0010] This problem is solved by a precision-stitch sewing machine of the type specified, which is characterized in that the guide element is movable between an advanced position and a retracted position relative to the seam line.

[0011] The concept of the solution upon which the present invention is based is that of causing the element for guiding the edging, which guide element resists and bears against the outer curved portion of the edging, to be retracted from the seam line when the first edge is retracted relative to the seam line by the hooked element. This prevents the position of the other edge of the edging to be displaced relative to the seam line causing slippage of the seam produced.

[0012] Further characteristics and the advantages of the machine according to the present invention will become clear from the following description of a preferred embodiment thereof, given by way of non-limiting example, with reference to the appended drawings, in which:

Figure 1 is a perspective view of a precision-stitch sewing machine according to the invention,

Figure 2 is a perspective view of a detail of the machine of Figure 1, on an enlarged scale,

Figure 3 is a perspective view of some components of the machine of Figure 1,

Figure 4 is an exploded perspective view of some components of Figure 3,

Figures 5 and 6 are a side view and a plan view of the components of Figure 3, respectively,

Figures 7 and 8 are a side view and a plan view of the components of Figure 3, respectively, in a different operative configuration,

Figures 9 and 10 show details of Figures 6 and 8, respectively,

Figures 11 and 12 are perspective views of some details of the machine of Figure 1 in two different stages of its operation.

[0013] With reference to the appended drawings, a precision-stitch sewing machine according to the invention for applying an edging 2 to an end 3 to be edged constituted, for example, by the waist of a sweater, is generally indicated 1.

[0014] The machine 1 comprises a frame 4 supporting a horizontal work surface 5 with which are associated: a sewing unit 6, a supply unit 7 for the end 3 to be edged, entrainment means 8 for the edging 2, and a folding unit 9 for encouraging the edging 2 to fold astride the end 3 to be edged, which are of known type.

[0015] The sewing unit 6 comprises an upright on which a sewing head 10 is cantilevered. A rod 11 extends along a vertical axis Z-Z from the free end of the sewing head 10 towards the work surface 5. The rod 11 is driven with a reciprocating motion along the vertical axis Z-Z by an electric motor of the machine 1 to which it is kinematically connected. The lower end of the rod 11 carries a needle 12 extending along the vertical axis Z-Z.

[0016] The work surface 5 supports a support table 13 for the edging 2 in a position beneath the sewing head 10 and parallel to the work surface 5. A vertical through-hole 14 is formed in the support table 13 to allow the needle 12 to move downwards during sewing.

[0017] A sewing region 15, identified between the sewing head 10 and the support table 13, is interposed between the folding unit 9 and the entrainment means 8 by means of which the edging 2 is advanced along a seam line X-X in order to be sewn to the end 3 to be edged by the needle 12 as will become clearer from the following description. The seam line X-X is parallel to the support table 13 and passes through the vertical axis Z-Z along which the needle 12 extends.

[0018] The support table 13 is substantially rectangular and is oriented so as to have a short side 16 parallel to the seam line X-X and at a predetermined limited distance therefrom.

[0019] The entrainment means 8 for the edging 2 comprise a pair of contrarotating rollers 17 supported by the frame 4 for rotating about respective parallel rotation axes extending in a direction Y-Y perpendicular to the seam line X-X and parallel to the support table 13. The rollers 17 are positioned downstream of the sewing region 15, with reference to the direction of advance of the edging 2, are disposed one above the other, and are disposed beside a long side of the support table 13 so that the edge 3 can be inserted between them. The rollers 17 are rotated by the motor of the machine 1, by means of a mechanical transmission of known type, not shown in the drawings, in order to entrain the edging 2 from the folding unit 9 and cause it to advance along the seam line X-X.

[0020] The unit 7 for supplying the end 3 to be edged comprises a flat belt 18 supported by a plurality of entrainment rollers for rotation along a closed path having a straight portion R parallel to the seam line X-X and beside the short side 16 of the support table 13 so as to be coplanar therewith.

[0021] The entrainment rollers of the flat belt 18 are supported for rotating by the frame 4 and are rotated by the motor of the machine 1 in order to advance the straight portion R of the flat belt 18 in the same direction in which the edging 2 advances along the seam line X-X.

[0022] The folding unit 9 comprises a tubular element 19 for guiding the edging 2, into which the edging 2, which is directed to the sewing region 15, is inserted. At the end at which the edging emerges from the tubular element 19, deflecting tongues 20 act on the edging 2 forcing it to fold over so as to be arranged along the seam line X-X with its respective edges flush with the short side 16 of the support table 13 and its concavity facing towards the straight portion R of the flat belt 18. As will become clearer from the following description, the folding unit 9 encourages the edging 2 to fold astride the end 3 to be edged which is transported by the flat belt 18.

[0023] The support table 13 comprises a guide element for resisting and bearing against the outer curved portion 21 of the folded edging 2 in the sewing region 15. This guide element is constituted by a plate 22 projecting from the support table 13 towards the sewing head 10 parallel to the short side 16 of the support table 13 but at a greater distance therefrom than the seam line X-X. The upper end of the plate 22 is curved towards the seam line X-X.

[0024] A side element 23 parallel to the sewing axis X-X extends from the short side 16 of the support table 13 towards the sewing head 10 in order to resist and bear against the lower edge 24 of the folded edging 2. The side element 23 is on the opposite side of the seam line X-X to the plate 22.

[0025] A flat bar 25 extending in the direction Y-Y is associated with the underside of the support table 13 so as to be slidable relative thereto.

[0026] In the embodiment shown, the slidable connection between the flat bar 25 and the support table 13 is formed by means of screws 26 having heads with larger diameters than their shanks. For each screw 26, the flat bar 25 has a slot 27 extending in the direction Y-Y and having a width intermediate the diameter of the shanks and that of the heads of the screws 26. The flat bar 25 is consequently held against the support table 13 by the heads of the screws 26 and can slide relative to the screws and relative to the support table 13 between an advanced travel limit position (Figure 5) and a retracted travel limit position (Figure 7) by a predetermined distance S equal to the axial lengths of the slots 27.

[0027] Upstream of the sewing region 15 and close to its short side 16, the support table 13 has an opening 28 in which a C-shaped bent end 48 of the flat bar 25 is inserted so as to be coplanar with the support table 13 in order to engage the lower edge 24 of the folded edging 2.

[0028] When the flat bar 25 is in its advanced travel limit position, the C-shaped bent end 48 is aligned with the short side 16 of the support table 13, whereas when the flat bar 25 is in its retracted travel limit position, the C-shaped bent end 48 is spaced from the short side 16 by the distance S in the direction away from the flat belt 18. During its movement from the advanced travel limit position to the retracted travel limit position, the C-shaped end of the flat bar 25 entrains the lower edge 24 of the folded edging 2, retracting it relative to the seam line X-X (Figure 12).

[0029] An L-shaped lever 29 is supported for pivoting at its angle 30 by a pin 31 supported by the frame 4 parallel to the axis X-X. The lever 29 has one end 32 engaged with the flat bar 25 in order to cause it to slide between the two travel limit positions and the other end connected by means of a vertical connection rod 33 to a chain 34 and an underlying pedal actuating device 35 fixed to the lower portion of the frame 4. When the pedal of the actuating device 35 is not operated, a helical spring 36 acts on the connection rod 33 urging it upwards so as to bring the flat bar 25 to the advanced travel limit position. Similarly, action on the pedal of the actuating device 35, brings the flat bar 25 to the retracted travel limit position against the action of the helical spring 36.

[0030] The plate 22 is carried by the end of a straight slide 38 which faces the short side 16 of the support table 13, the straight slide 38 being engaged for sliding in a groove 37 of the support table 13 extending in the direction Y-Y. The slide 38 is associated with the support table 13 by means of a knob 39 having a shank connected to the support table 13 by means of a male and female screw connection. In the region of the shank of the knob 39 the slide 38 has a slot 40 extending throughout its length in the axial direction Y-Y and having a width less than the diameter of the head of the knob 39. The slide 38 is consequently held against the support table 13 by means of the head of the knob 39 and can slide in the groove 37.

[0031] A cylindrical element 41 is inserted for sliding in the direction Y-Y in a corresponding through slot 47 in the support table 13, in the groove 37. The upper end of the cylindrical element 41 is connected to the slide 38 by means of a screw connection 42, whereas a pin 43 projects from its lower end in the direction X-X towards the flat bar 25. The slide 38, the cylindrical element 41 and the pin 43 are thus fixed for translation together.

[0032] A spring 44 acts on the pin 43 to keep it in abutment with an abutment plate 45 in a travel limit position (Figures 7, 10) in which it is retracted relative to the short side 16 of the support table. The abutment plate 45 is fixed to the support table 13 by means of a screw connection which enables its position relative to the short side 16 to be adjusted.

[0033] A peg 46 fixed to the flat bar 25 presses against the pin 43 to urge it into a more advanced position (Figures 5, 9) relative to the short side 16, against the action of the spring 44.

[0034] When the flat bar 25 is in its advanced travel limit position (Figure 5), the peg 46 acts on the pin 43 to keep the slide 28 and the plate 22 in an advanced position relative to the seam line X-X. It is appropriate to point out that, by action on the screw connection 42, it is possible to vary the distance between the plate 22 and the cylindrical element 41 so as to adjust precisely the distance H between the plate 22 and the short side 16 of the bearing surface 13 when the slide 38 is urged into the aforementioned advanced position (Figure 5).

[0035] When the flat bar 25 is brought by the lever 29 to the retracted travel limit position (Figure 7), the peg 46 ceases to act on the pin 43 so that the biasing action of the spring 44 brings the pin 43 into abutment with the abutment plate 45. This enables the plate 22 also to be retracted simultaneously from the seam line X-X by a predetermined distance which is adjustable independently of the travel of the flat bar 25, during the sliding of the flat bar 25 from the advanced travel limit position to the retracted travel limit position.

[0036] With reference to the appended drawings, when the machine 1 is in operation, the edging 2 emerging from the folding unit 9 is folded astride the end 3 to be edged of a sweater carried by the flat belt 18.

[0037] The edging 2 thus folded and the end 3 to be edged advance along the seam line X-X towards the sewing region 15. In this operating condition, since the pedal actuating device 35 is not operated, the flat bar 25 is in its advanced travel limit position and the plate 22 is urged to the advanced position towards the seam line X-X resisting and bearing against the outer curved portion 21 of the edging 2 (Figure 11). The lower edge 24 of the edging passes through the C-shaped end of the flat bar 25 and is resisted by the side element 23 so as not to advance beyond the short side 16 of the support table 13.

[0038] At the output of the sewing region, the edging 2 now sewn to the end 3 to be edged by the needle 12 is inserted between the contrarotating rollers 17 which entrain it, ensuring a continuous advance of the edging 2 still to be sewn in the sewing region 15.

[0039] When, towards the end of the sewing, it is necessary for a portion of one of the two edges of the edging 2 not to be sewn, a user of the machine 1 operates the pedal actuating device 35. This brings about retraction of the flat bar 25 to its retracted travel limit position (Figure 7), causing the lower edge 24 of the edging 2 to be retracted from the seam line X-X so that it is not sewn by the needle 12 (Figure 12).

[0040] The retraction of the flat bar 25 advantageously brings about a simultaneous retraction of the plate 22 from the seam line X-X by a predetermined distance which, as stated above, is adjustable in dependence on various requirements. The aforesaid retraction of the plate 22 enables the distance from the seam line X-X at which the outer curved portion 21 of the folded edging 2 is resisted and supported to be varied so as to prevent the retraction of the lower edge 24 of the folded edging from the seam line X-X causing the other edge of the edging to be displaced from the seam line X-X.

[0041] As can be appreciated from the description, the precision-stitch sewing machine according to the invention overcomes the problem referred to without having the disadvantages of the machines of the prior art mentioned.

[0042] Another advantage of the precision-stitch sewing machine according to the invention lies in the fact that it can be adjusted easily in order to adapt its operation to edging of different sizes and/or materials, avoiding the need to replace any components.

[0043] Another advantage of the precision-stitch sewing machine according to the invention lies in the fact that it is structurally and functionally simple so as to be reliable in operation.

[0044] Clearly, in order to satisfy contingent and specific requirements, a person skilled in the art may apply to the precision-stitch sewing machine described above many modifications and variations all of which, however, are included in the scope of protection of the invention as defined by the following claims.

Claims

1. A precision-stitch sewing machine for applying an edging (2) to an end (3) to be edged of a knitted item, a fabric or the like, along a predetermined seam line (X-X), of the type comprising:

- a folding unit (19) for encouraging the edging (2) to fold astride the end (3) to be edged, upstream of a sewing region (15) with reference to the direction of advance of the edging (2),

- a support table (13) for supporting the folded edging (2),

- an element (22) for guiding the edging (2) by resisting and bearing against the outer curved portion (21) of the folded edging (2),

- a hooked element (25) for engaging a first edge (24) of the folded edging (2), and

- actuating means (29, 33, 34, 25, 36) connected to the hooked element (25) in order to move it towards and away from a moved-away position in order to retract the first edge (24) from the seam line (X-X), relative to the other edge,

characterized in that the guide element (22) for the edging (2) is movable between an advanced position and a retracted position relative to the seam line (X-X).

2. A machine according to Claim 1, in which the element (22) for guiding the edging (2) is mounted on a slide (38) engaged for sliding in a groove (37) of the support table (13) extending in a direction (Y-Y) substantially perpendicular to the seam line (X-X).

3. A machine according to Claim 2, comprising resilient means (44) for resiliently urging the slide (38) into a retracted travel limit position, and in which the actuating means (29, 33, 34, 25, 36) push the slide (38) in opposition to the resilient means (44) to bring it to an advanced position relative to the seam line (X-X).

4. A machine according to claim 1, in which the element (22) for guiding the edging (2) comprises a plate (22) extending in a direction parallel to the seam line (X-X) perpendicular to the support table (13) and having an end curved towards the seam line (X-X).

5. A machine according to Claim 1, in which the first edge (24) of the edging (2) is that which is in contact with the support table (13).

6. A machine according to Claim 1, in which the hooked element (25) is slidable relative to the support table (13) in a direction (Y-Y) substantially perpendicular to the seam line (X-X).

7. A machine according to any one of Claims 1 and 6, in which the hooked element (25) comprises a bar having a C-shaped bent end (48) engaged with the first edge (24).

8. A machine according to Claim 1, in which the support table (13) comprises a side element (23) on the opposite side of the seam line (X-X) to the guide element (22) for the edging (2).

Drawing