IMPROVED MACHINE FOR SEWING FOOTWEAR

Abstract: A sewing machine implement consisting of a hollow arm (6) oscillating around an axis (7). At the upper end (6a) of said arm (6) there is provided a head (5) containing a loop taker (26), which is caused to rotate around said axis (7). Inside said head (5) there is provided a tubular operating assembly supported by and rotating in a seat (8) containing the aforementioned loop taker, said tubular operating assembly supporting needle plate (30). Differential transmission means (40a, 40, 38, 36, 34, 22, 21) housed inside said arm ensure that part (30) remains angularly motionless, notwithstanding the oscillations of arm (6).

Description: It is known that the crochet which works in conjunction with the needle in forming the stitches made by automatic sewing machines for footwear is located in a suitable seat formed in the head of a fixed support (arm or post). This design conformation leads to certain problems during the stage when the footwear is being sewn along the toe of the vamp, due to the specific shape of the latter, as well as in other areas of accentuated curvature (e.g. : the heel). The above problems arise from the difficulty of correctly inserting the head of the crochet in the toe of the vamp, as well as the difficulties encountered in making the portion of footwear being stitched slide evenly along the aforementioned head; this latter problem can lead to the formation of stitches of irregular length (in the direction of the line of stitches) in areas of accentuated curvature. The present invention avoids these problems through a series of modifications to an automatic sewing machine (see English Patent No. 2.118.219), taking the form of an inclined arm, the top end, or head of which features the seat for the crochet, the said arm swinging through an axis that coincides with the axis of rotation of the crochet. The aforesaid arm preferably comprises a first part, perpendicular to the above-mentioned axis, the upper end of which is fixed to the machine structure, and a second part which is fixed to the other end of the first part and inclined outwards in relation to the latter; the aforementioned crochet is mounted on the free end of this said second part. Suitable transmission means are housed within this said arm, and driven by motor means located in the machine casing, both of which are designed, in conjunction, to drive the aforementioned crochet so that it rotates. Since the axis of rotation of the crochet coincides with the axis upon which the arm swings, the two are independent of one another; in this way the operator can gradually position the arm in what is considered to be its optimum position without altering the synchronous operation of the needle and crochet. The head upon which the crochet is mounted is only slightly larger than the latter, conferring the advantage that the head can be used within the piece of footwear being worked upon, acting as a stop for the section of material being sewn, particularly in the toe and heel area. Positioning the head in areas of accentuated curvature is both made possible and facilitated by the action of the operator (either manually or by means of a pneumatic jack) on the above-mentioned arm. A technical problem which has not been solved by the above solution arises from the fact that the upper surface of the head, which the section of material being sewn rests upon, does not remain in a fixed position during the swinging movement of the arm due to the fact that it is an integral part of the latter. It is thus necessary for the slot in the head through which the said needle moves to have an angled orientation in order to avoid fouling by the needle during the swinging motion of the arm. In addition to this, the surface of the head moves in relation to the material above it when the arm swings, obliging the operator to take action, in relation to the length of stroke of the operating assembly (comprising a needle and at least one pressure foot, and which, as is known, is made to oscillate with an outwards and return motion in a direction perpendicular to the axis of rotation of the crochet) upon the material as it is being stitched in order to avoid the formation of undesirable ruckles or stitches of uneven length. From the FR-A-1 090 213, there is known a machine for sewing small bags, fitted with a rotatable curved arm. The machine includes a needle operated with a vertical motion and mounted on a tubular support which has to keep its attitude no matter of the rotation of the arm. To obtain this a toothed wheel is connected to the tubular support and is linked, by means of a chain, to another toothed wheel which is in turn keyed on the upper end of a vertical shaft. The lower end of the shaft has keyed onto itself another toothed wheel, linked by means of a chain to a fourth tothed wheel fixed to the frame of the machine. When the arm is rotated, the shaft lower end toothed wheel is made to rotate so that the shaft rotates too. In this way the shaft upper end toothed wheel rotates thus making the tubular support to rotate in the direction opposite to the direction in which the arm rotates, and the needle always keeps its originary attitude. The machine described in the FR-A-1 090 213, is not very precise in keeping the attitude of the tubular support, since it provides for using chains and toothed wheels, which, as it is known, does not match together with high precision. Moreover, this arrangement can be adopted only if the arm is curved in two squared angles, because the link between the chains and the toothed wheels can be set only according to a 90 degrees angle. The object of the present invention is to propose a machine of the above type, the head of which features a support surface for the section of material being sewn which is unaffected by the swinging motion of the arm as well as the rotating motion of the crochet, and which can, if necessary, be driven with an oscillating motion in relation to the axis of the latter, in synchrony with the movement of the operating assembly above it. A further object of the invention is to incorporate improvements which enable the axis upon which the swinging arm moves and the axis of rotation of the crochet to be coaxial, irrespective of the position to which the swinging arm is moved. The above objects are achieved by the invention as described in claims 1 to 6 below. The characteristics of the invention are emphasised hereinafter with specific reference to the attached tables of drawings, in which: Figure 1 is an illustration in perspective of the improved automatic sewing machine for footwear which is the subject of the present of invention, in a first embodiment; Figure 2 is a diagrammatic representation in section of the improvements proposed for the structure shown in Figure 1, the said section running along the plane of symmetry of the swinging arm; Figure 3 is an exploded view, in perspective, of the parts forming the operating head of the machine in the first embodiment, this head being located at the outer extremity of the swinging arm. Figure 4 is a perspective view of the structure of the automatic sewing machine obtained in a second embodiment; Figure 5 is a diagrammatic representation in section of the improvements proposed for the structure shown in Figure 4, the said section running along the plane of symmetry of the swinging arm; Figure 6 is a diagrammatic representation of the improvements shown in Figures 4 and 5, with reference to their space development; Figure 7 is an exploded view, in perspective, of the parts forming the operating head of the machine obtained in the second embodiment, this head being located at the outer extremity of the swinging arm. With reference to the figures 1,2 and 3, 1 indicates the casing of an automatic sewing machine fitted with an operating unit 2 (shown in outline in that of known type) which works in conjunction with an operating assembly 10, comprising a vertical needle 3 for feeding the thread, and at least one pressure foot 4, both of which face downwards. The means located in the unit 2 are designed, as is known, to drive the said needle and pressure foot vertically in appropriate synchrony, as well as to move the said operating assembly through a vertical plane with an oscillating motion (direction S) in order to transport the material to be sewn (not illustrated) resting upon a head located below, indicated in outline by 5, and described below. The head 5 is located upon the upper end 6a of a hollow arm 6, the other end of which is supported by the casing such that the arm itself is able to turn and swing upon an axis 7 perpendicular to the above-mentioned plane. The arm 6 principally comprises two portions, 6b and 6c in that order, moving away from the said upper end, and respectively inclined in relation to axis 7, and perpendicular to the latter. The upper part of the head 5, which is open on the side opposite the casing 1, forms a seat 8, coaxial to axis 7. This same head 5 supports a shaft 9, coaxial to the said axis 7, so that it is able to turn, and which is driven with a rotating motion by first transmission means comprising, in order, a crown wheel and pinion 10, a shaft 11, a crown wheel and pinion 12, a shaft 13 (located in portion 6b), a crown wheel and pinion 14, a shaft 15 (located in portion 6c), and finally, another crown wheel and pinion 16, the end pinion 16a of which is coaxial to axis 7; known motor means, not illustrated, drive shaft 17 of the pinion 16a. The fact that shafts 17, 9 are coaxial to axis 7 makes it possible for shaft 9 to rotate independently of the oscillating movement of arm 6. A bush 21, the inside edge of which has a toothed surface 22, is inserted as a free fit in seat 8; a peripheral area of the bush features a cut-out 23, whilst the remaining edge of the bush (that without the toothed surface) features two notches 24 in the same plane of the diameter. Inside the bush, there is a ring-shaped surface 25 which is struck by one side of a crochet 26 (e.g. : of the type with a shuttle of thread). 27 indicates a ring comprising two coaxial sections 27a, 27b, the first of which is designed to be inserted as a free fit in the bush 21 on the side without the toothed surface, until the second section comes up against the adjacent head of the bush; when the ring is inserted, two pins 28, which are an integral part of the ring 27, are inserted in the corresponding notches 24. The ring-shaped surface 25 and the head of the first section 27a form a seat in which the crochet is located as a free fit. A lug 29, keyed to shaft 9, is inserted in seat 26a, formed due to the special shape of the crochet; this enables the latter to be drawn round so that it rotates coaxially to axis 7. The second section 27b of the ring 27 features a radial projection 30 which is located on the outer side of the bush and upper end 6a when the pins 28 are inserted in the notches 24. The projection 30 features a slot 31 that is centred in relation to the cut-out 23 below it. Inserting the pins 28 in the notches 24 on the one hand enables the orientation of the slot 31 in relation to the cut-out 23 to be maintained, and on the other hand makes the ring 27 and bush 21 rotate together as if one piece. A closing ring 32, mounted on the upper end 6a using locking means 33 so that it is unable to move, avoids the possibility of the tubular operating assembly, comprising the said ring and bush, sliding out of the seat 8. The aforesaid tubular operating assembly is made to oscillate in relation to axis 7 by second transmission means subject to the action of control means located in the casing 1. With reference to a first embodiment of the invention (Figures 1,2 and 3), the second transmission means comprise, in order, a pinion 34, engaging with the toothed surface 22, formed on the upper end of a tubular element 35 (within which the above-mentioned shaft 11 is inserted as a free fit), a crown wheel and pinion 36, a tubular element 37 (within which the above-mentioned shaft 13 is inserted as a free fit), a crown wheel and pinion 38, a shaft 39 and, finally, a further crown wheel and pinion 40, the control pinion 40a of which is coaxial to the axis 7. In the case illustrated in Fig. 2, the pinion 40a idles on its own shaft 41 which is coaxial to the axis 7; the shaft 41 is mounted on portion 6c. An arm 42, (representing the aforementioned control means), is mounted on pinion 40a, and is at the same time mounted on the casing 1. When the arm 6 rotates, the second transmission means move as a consequence, due to the fact that the pinion 40a is kept in the fixed position. In the case under consideration, an angular swinging movement by arm 6 in a given direction is accompanied by an equal angular oscillating movement by the operating assembly in the opposite direction: this enables the position of the projection 31 to be kept unaltered in relation to the operating assembly above it, and in particular the needle 3. In this way a base (i.e. the aforesaid projection) is formed on the operating head, which remains fixed in relation to the needle and in relation to the material to be sewn, located resting upon this base, and thus uninfluenced by the spatial orientation of the arm 6. In this way any relative sliding motion between the support base and material to be sewn, resulting from the swinging movement of the arm, is eliminated. The solution described above makes it possible to move the above-mentioned tubular operating assembly with an oscillating motion that is in synchrony with the oscillating motion of the operating assembly; the pinion 40A must for this purpose be subjected to the action of the drive means of the operating assembly itself. The second means of transmission engage, by means of the toothed surface 22, with the bush 21 and can alternatively engage with the toothed surface (not illustrated) on the ring 27: the result obtained is the same as that already described. The second means of transmission can also be completely or partially outside to the arm 6. In another embodiment, at the control pinion 40a, a fixed toothed surface (not illustrated) can be made in the casing 1 describing an arc on a coaxial circumference with axis 7; the said toothed surface engages the lower part of the element 37, through suitable transmission means (not illustrated), with the said element 37 outside the arm 6 which conveniently supports it. In this latter embodiment, the remaining components of the second means of transmission (i.e. crown wheel and pinion 36 and element 35) can also be, as an alternative to the manner already described, outside the arm 6, and in particular outside the upper end 6a of the said arm, engaging with the ring 27. In the second embodiment, the aforementioned second means of transmission are formed and positioned as shown in Figures 4, 5, 6 and 7. The aforementioned second means are made up of two inelastic cables 100 and 110 with their ends 100a and 110a fixed to corresponding clamps 71a and 71b fixed to the casing 1, and their other ends 100b and 110b fixed to the ring 27 symmetrically opposed on either side of the said ring. Starting from the clamps 71a, b, the said cables are first guided by a cylindrical guide 72 mounted on the upper portion of section 6c of the arm 6, coaxially to the axis 7: it should be noted that the said cables are partially wound round, from opposite sides, the said guide. Next, the cables slide over coaxial, curved guides 73a and 73b located on opposite sides of the lower portion 6c of the arm 6, and then, in the intermediate section 6b of the arm 6, pass through two sheaths 74a and 74b which cross over each other; the said sheaths are located inside the last section 6b and the upper end 6a of the arm 6. The cables finally come out of the said sheaths so that their ends 100b, 110b can be fixed directly to the ring 27. In the second embodiment, the head 5 (Figure 7) is similar to that illustrated in Figure 3 with the exception that in this embodiment the bush 21 does not have the toothed surface. A suitable, specific cable length in conjunction with the tensioning guide function performed by the guide 72, the guides 73a, b and the sheaths 74a, b, keep the said cables correctly tensioned irrespective of any swinging motion of the arm 6. In this embodiment also, moving the arm 6 in the direction or another does not alter the position of one projection 30 in relation to the needle 3 situated above it. In fact (see Figure 6), rotating the arm 6 in direction H by a preset angle, causes the ring 27 to rotate towards K, in the opposite direction to H, by the same degree; this is due to the fact that the cables are inelastic and the fact that the sheaths 74a, b are crossed over each other. As a consequence, the seat 8 rotates in direction H but the operating assembly (ring 27 - bush 21) rotates, in relation to the said seat, to the same degree but in the opposite direction K thus keeping the said assembly fixed in relation to the needle above it. A plate 80 is mounted on the common ends of portions 6b, 6c, supporting pins upon which idle corresponding rollers 19 that slide on contact with corresponding fixed circular guides 20 that are integral part of the casing and coaxial to axis 7. The function of these said rollers is to guide the arm during its swinging movement: in this way avoiding any flexing of portion 6c, which is advantageous to ensuring that shaft 9 is constantly coaxial to axis 7. The improvements proposed by the present invention by definition involve driving the support base of the head 5 independently of the rotation of the crochet and swinging movements of the arm, conferring the advantage that the said support base can be maintained in a stationary position in relation to the needle, or made to oscillate in synchrony with the oscillating motion of the latter, particularly in the first embodiment described above (Figures 1,2 and 3). The production of sewing stitches using the above machine is clear to experts in the sector. In the present case, it has been assumed that the crochet is fitted with a shuttle with thread, such that what is known as a "lock-stitch" is effected. The needle 3 works in conjunction with the crochet in producing the aforesaid stitch in that it moves through the above-mentioned slot 31 and cut-out 23. It is left as understood that it is also possible to use different types of rotating crochets, such as, for example, those used for producing what is known as "chain-stitch". The advantages of the English patent No. 2.118.219 (referred to in the introduction) remain unchanged, due to the fact that the invention uses a crochet located in the outer extremity 6a of the arm 6, which also rotates upon an axis coincident to the axis 7 upon which the arm 6 is able to swing. The arm 6 can be operated manually, or using known means (e.g. pneumatic jack) controlled by the operator. As has been stated, the rollers 19 work in conjunction with the guides 20, with the function of exerting a stiffening action on the arm 6, this having a positive effect in maintaining, over time, the coaxiality of the axis of the crochet and tubular operating assembly and the axis 7 through which the arm 7 swings.

Claims: Machine for sewing footwear comprising at least one vertical needle (3), an arm (6) connected to the casing (1) of the machine so that said arm (6) is able to turn upon a horizontal axis (7), the said arm (6) comprising a portion (6b), that is inclined with respect to said horizontal axis (7), and a vertical portion (6c) that is perpendicular with respect to the same horizontal axis (7); a head (5) supported by the outer extremity (6a) of said arm, below said needle (3), to hold the material to be sewn, and featuring a seat (8) in which a crochet (26) is located; first transmission means, located inside the said arm, operated by motor means housed in the said casing to drive the said crochet; the said machine being characterised in that it includes: a first element (35) located in the above-mentioned extremity (6a); a second element (37) located in the above-mentioned inclined portion (6b) and connected to the first element by a crown wheel and pinion (36); a third element (39) located in the portion (6c) of the said arm perpendicular to the said horizontal axis (7), this third element (39) being connected to the second element by means of a crown wheel and pinion (38); a control pinion (40a) engaging with a corresponding pinion located in the upper end of the said third element (39); a bush (21) rotatably supported by said seat (8) formed in the said head (5), said bush featuring a toothed surface (22) which engages with a pinion (34) formed on the upper end of said first element (35), with a cut-out (23) made on the periphery of said bush (21); a ring (27) featuring at its upper part a radial projection (30) this radial projection (30) in turn featuring a slot (31) that is centred in relation to said cut-out (23), the said ring comprising two consecutive coaxial sections (27a, 27b), with the first section (27a) being freely inserted in the said bush, on the side not featuring the said toothed surface; means for orienting said slot (31) so that it is kept coaxial to the said cut-out (23) above it, and for engaging the said ring and bush with one another so that they rotate together. Machine for sewing footwear comprising at least one vertical needle (3), an arm (6) connected to the casing (1) of the machine so that said arm (6) is able to turn upon a horizontal axis (7), the said arm (6) comprising a portion (6b), that is inclined with respect to said horizontal axis (7), and a vertical portion (6c) that is perpendicular with respect to the same horizontal axis (7); a head (5) supported by the outer extremity (6a) of said arm, below said needle (3), to hold the material to be sewn, and featuring a seat (8) in which a crochet (26) is located; first transmission means, located inside the said arm, operated by motor means housed in the said casing to drive the said crochet; the said machine being characterised in that it includes: a bush (21) rotatably supported by said seat (8) formed in the said head (5), said bush featuring a cut-out (23) made on its periphery; a ring (27) featuring at its upper part a radial projection (30) this radial projection (30) in turn featuring a slot (31) that is centred in relation to said cut-out (23), the said ring comprising two consecutive coaxial sections (27a, 27b), with the first section (27a) being freely inserted in the said bush; means for orienting said slot (31) so that it is kept coaxial to the said cut-out (23) above it, and for engaging the said ring and bush with one another so that they rotate together; at least two inelastic cables (100, 110) with their ends (100a, 110b) fixed to the casing (1) of the machine and their other ends (100b, 110b) fixed to said bush (21); guiding and tensioning means on said arm (6) to guide and tension said cables. Machine as in claim 2, characterised in that the said means for guiding and tensioning the said cables consist of: a cylindrical guide (72), on the upper part of portion (6c) of the arm (6), the said cylindrical guide being situated on the said horizontal axis (7) and partially wound round from opposite sides, by said cables (100,110); at least two curved guides (73a,b), located on the lower part of portion (6c) of the said arm (6) on which the aforementioned cables slide; at least two sheaths (74a, 74b), which cross over each other, through which the aforementioned cables pass and from which these cables exit so that they can be fixed to the aforementioned tubular operating assembly. Machine as in claim 1 or 2, characterised in that said means for orienting said slot (31) comprise at least one pin (28) formed as a part of the said bush (21) or of the said ring (27), and engages in a corresponding seat (24) in the said ring (27) or said bush (21) respectively. Machine as in claim 1 or 2, characterised in that it includes means for stabilising the swinging motion of the said arm comprising at least one roller (19), mounted so that it idles on the relevant axis delimited by the common ends of the aforementioned portions (6b, 6c) of the arm (6), sliding between fixed guides (20), having a circular development coaxial to the said axis (7), and fixed to the casing (1) of the machine. Machine as in claims 1 or 2, characterised in that the said second means are composed of transmission parts which engage on one side, through gearing with the said tubular operating assembly, and engage on the other side with a fixed toothed surface on the machine casing (1) and coaxial to the rotation axis (7) of the arm (6), engaging said parts in such a way as to cause the aforementioned assembly to rotate in the opposite direction to the direction of rotation of the said arm to an amplitude equal to that of the swinging motion of the said arm. Machine as in claim 6, characterised in that the aforementioned transmission parts are in part, at least, external to the aforementioned arm which supports them.

Inventors: CIUCANI, MARIO, VALSECCHI, GIOVANNI
Applicants: CIUCANI, MARIO, MEC-VAL S.R.L.
Application year: 1988
Main classification: D05B15
IPC codes: D05B15, D05B73