FR2492856A1 - SEWING MACHINE HAVING A TRANSVERSALLY MOBILE TRAINING JACK - Google Patents

Abstract

The invention relates to a sewing machine 10 of the type comprising a driving claw 15 arranged to move transversely. THE MACHINE INCLUDES A CARRIER SHAFT 16 FOR THE SAID CLAW 15, THIS SHAFT BEING ORGANIZED TO MOVE AXIALLY IN OPPOSITION TO THE ACTION OF AN ELASTIC ORGAN 80; A DECODING UNIT 20, 25 DESIGNED TO RECEIVE THE CONTROL SIGNALS FROM A PROCESSING UNIT AND TO TAKE THREE WORKING POSITIONS FOLLOWING THAT THE SAID CLAW 15 MUST EXECUTE A TRANSVERSAL MOVEMENT TOWARDS THE RIGHT, A TRANSVERSAL MOVEMENT TOWARDS THE LEFT TRANSVERSAL MOVEMENT; AND A LINKAGE 23, 17, 40 WHICH CONVERTS EACH OF THE SAID WORKING POSITIONS INTO A CORRESPONDING PIVOT OF AN ARM 57 PROJECTING RADIALLY FROM A SHAFT 42 COUPLES AXIALLY AUDITED CARRIER SHAFT 16 OF THE SAID CLAW 15; LEDIT ARM 57 CARRYING A ROLLER 58 WHICH CAN ROTATE AROUND ITS AXIS AND WHICH CAN SLIDE ON A SURFACE OF A PROFILE 65 CONNECTED TO A FIXED PART OF THE SAID MACHINE 10. APPLICATION IN THE FIELD OF SEWING MACHINES.

Description

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  The present invention relates to a sewing machine having a transversely movable driving claw. In particular, the invention relates to a sewing machine in which it is provided, in addition to mechanisms which control the transverse movement of the needle-carrying arm. and the movement of the claw that drives the fabric forward and / or backward, a mechanism that allows the control of transverse movement

of the driving claw.

  In such machines, the feed dog is therefore effectively subjected to two types of movement, the first of which is carried out in a vertical longitudinal direction and ensures the transport of the fabric.

  in the forward and / or reverse direction while the se-

  cond occurs in a transverse direction and allows the fabric to be transported to the left or to the

  right relative to said direction of advancement.

  At present, the mechanisms used to

  the control of the transverse movement of the claw of

  essentially consist of a feeler

  which is pushed by an elastic means so as to cooperate

  frontally with a cam and which converts, using a linkage, the variations of the contour of the cam

  in transverse movements of the claw.

  Although the known mechanisms are widely used in some of the currently available sewing machines, they have certain disadvantages. For example, we need to use different cams to produce different cycles of transverse movements of the claw

  of training so that it is necessary for the

  each time to mount the appropriate cam

  asked. In addition, the transverse movements of the tissue are

  always limited to the radius of action of the cam: consequently

  it is not possible for the machine to perform embroidery work that is oriented in one direction

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  transversal beyond a certain maximum limit. In-

  In the end, these mechanisms have a low accuracy and are

particularly complicated.

  An object of the invention is to provide a sewing machine which does not have the aforementioned drawbacks

machines of known types.

  This goal as well as others that will appear in

  course of the present description, is reached according to the

  present invention by a sewing machine of the type com

  taking a feed dog arranged to move transversely, characterized in that it comprises a support shaft of said feed dog, said carrier shaft being arranged to move axially

  in opposition to the action of an elastic means; a deco

  arranged to receive the control signals from

  from a processing unit and to take three posi-

  working conditions according to which said claw must move

  crosswise increment to the right, of a

  transverse crease to the left or no increment

  cross section; and a linkage which converts each of these working positions into a corresponding angular pivoting of an arm extending radially from a shaft axially coupled with the claw support shaft, which arm carries a rotatable roller its axis and slidable on a surface of a profiled element connected to a fixed part of the sewing machine.

  Other advantages and features of the invention

  will be highlighted in the rest of the description.

  1, a perspective view of a sewing machine according to the present invention, FIGS. 2, 3 and 3 are diagrammatic views of a sewing machine according to the present invention. 4 and 5 are views showing certain details of the machine according to FIG. 1, and FIG. 6 is a graphical representation giving the profiles of the vertical movements "v" (FIG.

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  transverse movements "t" (Fig. 6b) of the baby claw

  Trapping of the sewing machine according to Figure 1.

  In FIG. 1, the numeral 10 desires

  A sewing machine as a whole comprises a base 11 and a supporting column 12 extended transversely by an arm 13 which supports a needle 14. The machine 10 comprises a driving claw 15 which is

  carried at one end of a shaft 16, the other end of which

  mity is connected to the output of a training device

  17 shown in detail in FIGS. 2, 3 and 4.

  The machine 10 also comprises a decoding unit 20 of known type, which comprises in particular two bars 21, 22 each of which can respectively take a rest position or a working position so as to be partially retained within the unit. 20 or else that can be pushed outwards, as shown in Figure 2. The unit 20 is essentially an electromechanical decoder which receives an electrical signal from a processing unit (not shown) and which converts said signal in a corresponding movement of the bars 21 and / or 22, so that it is possible to establish different cycles consisting of different combinations of the aforesaid movements in relation to the

  program content stored in the processing unit.

  Between bars 21 and 22 and the control input

  of the driving device 17, a rod is provided.

  transmission link 23, which will be described hereinafter with reference to FIG. 2. In more detail, the linkage 23 is constituted by two arms

  tippers 25, 26, the opposite ends of the first

  sliding in the slots 27, 28 formed in the

  ends of each of the bars 21, 22. The swinging arm

  their 26 is rotatably mounted about a bearing pin 30 and one of its ends is connected to a central rod 29 of the rocker arm 25 while its other end is connected to a stick 32 carried by a

  end of a bar 31. The latter is mounted on a

  votively by its other end on the end of a

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  U-shaped arm 33 extending radially from a cylindrical member 34 rotatably mounted on a pivot

  carried by a wall 36 (Figure 3) of the frame of the machine.

  10. The cylindrical element 34-part an appendix 38 whose forked end is attached to an appendix

  corresponding 39 projecting radially from a slide

  bucket 40 essentially consisting of a tubular element

  re 41 which slides axially on a shaft 42.

  The surface of the tubular element 41 comprises three radial notches 44 which are each arranged to be meshed instantly by a bar

  elastic strap 45 fixed at one end to a wall

  aunt 46 (Figure 3). An arm 48 projects radially from the element 40 and has a referenced end 49 which is profiled in an arc of a circle, and which is arranged to cooperate with three cams 51, 52, 53 which are keyed

  on a shaft 50 which is itself connected to a drive mechanism

  in a manner not shown. In particular,

  cam 52 is essentially constituted by a circular disk

  eyepiece mounted in an axial position on the shaft 50

  say that the cams 51 and 53 are mounted on the sides

  opposed to the cam 52 and, with respect to the circular contour

  re of the cam 52, they each comprise a tooth which has the same angular extent in each case and which protrudes outwards, this tooth being followed

  by a cavity that extends below the profile of the

  52, and vice versa, so that during a rotation of 3600 of the shaft 50, the end of the arm of the slider first meets the tooth and the cavity if

  the arm 48 is positioned on the caries 53 or else in

  cavity and then the tooth if the arm 48 is posi-

on the cam 51.

  From the tubular element 41 of the slider 40 projects an appendage 55 curved at 90 'and comprising at its end a forked portion 56 which is hooked on a shaft 57 oriented radially and angularly coupled with the shaft 42. At the end distal from the shaft 42, the arDre 57 carries a roller 58 which can rotate about its axis

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  and which is retained on the shaft 57 by means of a nut 59 and a locking nut 60 which are screwed onto a threaded end 61 of the shaft 57. Said end 61 is fixed on a support 62 by via a cylindrical spring 63 which acts, via the shaft 57, so as to always maintain the arm 48 of the slider 40 applied against the surface of one of said cams 51, 52, 53. Finally , the roller 58 cooperates with the

  surface of a frustoconical portion 65 placed at one end

  a cylinder 66 which is screwed into a load-bearing wall

  67 of the frame (not shown) of the machine 10.

  Referring more particularly to FIGS. 2 and 4, it can be seen that the shaft 42 has at its ends

  two pins 69 and 70, the first of which is rotatably mounted

  in a bore formed in a bearing wall 71 while the second cooperates frontally with a ball 72 and is maintained, as well as this ball, in a circular seat in a carrier member 73. The latter is connected angularly using a screw 74 to the shaft 16 which is supported at its ends by the walls 75, 76 forming part of the frame of the sewing machine 10. In known manner, by means of a crank mechanism 78, the shaft 16 supports the feed dog 15, which is supported by a shaft 79 forming part of said crank mechanism and which is rotatably mounted about its axis. To this shaft 79 is connected a rather stiff elastic blade 77 which is mounted radially on

  this shaft 79 and one end of which rests on the surface

  this bottom of the base 11 in order to apply to the shaft 79

  a torque that prevents the claw 15 from

  arbitrarily from his rest position.

  Referring more particularly to Figures 2, 4 and 5, it is seen that an elastic blade 80 is mounted on the outer surface of the wall 76 by means of screws 81 and a plate 82. The end of this blade elastic 80 cooperates frontally with the end portion of the shaft 16 so as to axially push the latter in the direction of the wall 75 and, referring to the

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  2, so as to push the shaft 42 axially so that the roller 58 is always maintained at

  contact of the surface of the frustoconical portion 65.

  In FIGS. 2, 4 and 5, reference numeral 84 denotes a mechanism arranged to control the cyclic rise of the driving claw 15 during a sewing cycle. The mechanism 84 essentially comprises a shaft 85 which carries at one end an arm

  radial 86 cooperating with the lower surface of the grif-

  15 and which carries at its other end a radial arm 89 on which is mounted a pin 90 which supports a

  roller 91 so that it can rotate and slide

  axially. This roller 91 bears against a cam member 96 keyed on the shaft 50 and is maintained

  applied against that tree by the force exerted by the

  elastic band 77 on the arm 85 (connected to the roller by the

  arm 89) by means of the shaft 79 and the feed dog.

  15, which rests on the arm 86 also projecting from the shaft 85. The element 96 is essentially

  constituted (FIG. 4) by a cam part 97 and a part

  98, these parties facing each other.

  Considering more particularly Figure 2,

  it can be seen that the roller 91 is mounted so as to be able to

  smooth along the trunnion 90 and that its position along said trunnion may be selected by means of a manually operable bar and comprising one end

  fork 101 which engages roller 91. At the opposite end

  end of this end 101, the bar 100 comprises a

  rectangular check mark 102 arranged to engage

  in an opening 103 of the load bearing wall 71 of the

  China in opposition to the action of a return spring 105.

  The portion of the bar 100 which includes the notch 102 is accessible to the operator and, under normal operating conditions of the machine 10, it is in the position shown in Figure 2, which corresponds to the positioning of the roller 91 on the cam 97. In a different working position, the notch 102 is engaged in the opening 103 so that the roller 91 moves

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  axially along the pin 90 and brought into contact

with the surface of the disk 98.

  We will now describe the operation of the

  sewing machine 10 with reference to FIG.

  As indicated above, the bars 21 and 22 of the decoding unit 20 may take a first or a second working position. FIG. 2 represents a working position in which the bar 21 is

  retracted while the bar 22 is pushed towards the ex-

  interior so that the pin 29 of the rocking arm is in an intermediate position between two limit positions that can take according to the two bars 21, 22. are respectively retracted or pushed

outwards.

  The position taken by the nipple 29 of the swinging arm

  25 in FIG. 2 is such that, through the intermediary of

  re of the rocker arm 26, the bar 31, the arm 33 and the appendix 38 of the element 34, the slide 40 is positioned so that its arm 48 rests on the intermediate cam 52 of the assembly cams 51, 52, 53 (see also FIG. 4). Since the cam 52 is

  consisting essentially of an axial cylinder, the rotation

  tion of the shaft 50 does not produce an angular movement of the slider 40, so that the roller 58 carried by the shaft 57 remains stationary and therefore the shaft 42 also remains at rest. In such conditions, the shaft 16 receives no axial thrust from the shaft 42: it is therefore maintained in its rest position by the elastic blade 80. The sewing machine 10 therefore performs the cycle of sewing

  classic, the rising movements of the claw of

  dragging 15 being controlled by the shaft 85 through the

  cam 97 and being synchronized with the

  of the needle 14 so that the tissue is moved

  essentially forward or backward in

  cordance with the rotational movement transmitted to the shaft 16 by a feed mechanism, not shown but of

known type.

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  We will now assume that the two bars 21

  and 22 of the decoding unit 20 are retracted. In con-

  Sequence (FIG. 2), the stick 29 of the rocker arm 25 is moved upwards and the bar 31 is consequently moved downwards by means of the tilting arm 26. As a result, the element 34 rotates in the direction of rotation. meaning

  clockwise and move the slide

  bucket 40 so that his arm 48 comes to rest

on the surface of the cam 51.

  Referring to Figure 3 and assuming

  that the shaft 50 rotates in the opposite direction of the

  clockwise, the cam 51 initially produces a

  slider 40 in the opposite direction of the

  of a watch around its axis (shaft 42), this movement being followed by a clockwise movement until it reaches a point

  position opposite to the maximum position

  quoted, then it finally performs a movement in the opposite direction of the clockwise to return to its original position. The pivoting of the shaft 42 about its axis causes via the

  forked part 56 of the corresponding movements of the

  57 and consequently cause the roller 58 to slide on the corresponding surface of the frustoconical portion 65

  provided at the end of the cylinder 66. In the example

  (Figure 3), the roller 58 is first pushed towards the larger diameter area of the portion 65, then it moves until it reaches the minimum cross-sectional area, and finally it returns to the intermediate zone of the portion 65. Because the roller 58 is rotatably mounted on the shaft 57 and the latter is fixed on the shaft 42, the movements of the roller 58 produce an axial movement of the shaft 42, this movement being transmitted to the shaft 16 which controls the movements of the

scratch 15.

  In the example described below, the shaft 16 is driven to move, against the action of the elastic blade 80, first in order to progress

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  its axial position outwards and then back back in correspondence with the outer surface of

  wall 76 and then return to an intermediate position

  rest. The axial movements of the shaft 16 and consequently the transverse movements (t) of the claw 15 have been highlighted on the first part of FIG. 6b, during a complete sewing cycle which is considered as covering a 360 angle. FIG. 6a shows in correspondence the vertical movement (v) of the claw 15 under the control of the shaft 85. Comparing these two graphs, it can be seen that the claw is first displaced from left to right (FIG. 2) before being lifted. Then, in the intermediate zone where it is raised, it is also driven from right to left. Finally, when she comes down again, she returns to her position

  initially so that the transverse displacement is zero.

  Such a process of moving the claw 15 makes

  so that the fabric leaning on it moves trans-

  from right to left in a distance

  this predetermined (Figure 2) or from the left to the

  right (Figure 1). In conclusion, referring to the

  1, the claw 15 causes, during a cycle

  ture, a movement of the fabric to the right over a unit distance of a predetermined value in

the example considered.

  An exactly opposite behavior occurs, with a transverse movement of the fabric to the left, when the two bars 21 and 22 of the decoding unit 20 are pushed outwards. In this case, the arm

  48 of the slider 40 slides on the cam 53: consequently

  When the roller 58 is first moved to the minimum cross-sectional area of the frusto-conical portion 65, it then executes a complete race from this zone to the maximum cross-sectional area, and it finally returns to the intermediate zone. The tree 16 is

  now pushed in the opposite direction to the previous

  dente and it changes its axial position, as indicated in

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  the second part of Figure 6b, so that it moves first to the left while the claw is still lowered, then it moves to the right while the claw is raised, then it returns to its original position while the claw is lowered. In this case, the claw 15 forces the fabric to perform a movement from left to right (Figure 2), or, (Figure 1) a transverse movement to the left

  a predetermined value for each sewing cycle.

  Finally, according to Figures 4 and 5, the choice of

  axial position of the roller 91 along the trunnion 90 determines

  In this respect, the fabric moves only when the claw is raised which occurs only when the roller 91 slides on the cam 97. The operator can slide the roller 91 on the disc 98 by acting on the lever 100 so that the notch 102 engages in the slot 103. In this case, the claw 15 is no longer driven upwards by the arm 86 and therefore it can not

no longer pull the fabric.

  An examination of the characteristics of the machine 10 according to the present invention shows that it allows

  to achieve the objectives defined above.

  Firstly, the described mechanism acts with great precision because a play occurring in the linkage ensuring the connection of the bars 21 and 22 with the shaft 16 has no influence on the positioning accuracy of this shaft 16 This is explained by the fact that the axial movements of the shaft 16 depend on the movements of the shaft 42 and, as indicated above, the angular position of said shaft which is determined solely by the position of the roller 58 on the surface of the frustoconical portion 65. In addition, it is possible using a single mechanism (roller 58 and part 65) to control the transverse movements of the claw 15 both to the left and to the right without no limitation: it is only necessary to repeat a transverse movement of the claw 15 in the same direction during it 2492856

  the necessary number of cycles to produce movements

  tissue that could not be obtained with

  devices known at present.

  It is no longer necessary to intervene manually

  cams because all movements are controlled by the decoding unit 20 which, as indicated above, is controlled by a control unit.

  treatment in a completely automatic way.

  Naturally, the invention is not limited to the embodiments described above and shown, from which we can provide other modes and other embodiments, without that out

of the scope of the present invention.

Claims (5)

R E V E N D I C A T I ONS   1.- Sewing machine (10) of the type comprising a   driving claw (15) arranged for trans-   Versalement characterized in that it comprises a carrier shaft (16) for said claw (15), said carrier shaft being arranged to move axially in opposition   to the action of an elastic member (80); a unit of   encoding (20, 25) arranged to receive the control signals from a processing unit and to take three work positions according to whether said claw (15) is to perform transverse movement to the right, transverse movement to the left or no transverse movement; and a linkage (23, 17, 40) which converts each of said working positions into a corresponding pivoting of an arm (57)   protruding radially from an axially coupled shaft (42)   said bearing shaft (16) of said claw (15); said arm (57) carrying a roller (58) rotatable about its axis and slidable on a surface of a shaped member (65) connected to a fixed portion of said machine (10).   2. Sewing machine according to claim 1, characterized in that said decoding unit (20, 25)   comprises a decoding element (20) of   which is arranged to receive electrical control signals at its input and to produce an output signal which passes two bars (21, 22) in a   first or second position; and a swinging arm   their (25) comprising end portions connected to respective end portions of said bars (21, 22), said rocker arm comprising in the center a pivot (29) which is arranged to take a first, a second and a third working position by correspondence with the three aforementioned working positions, according to whether said bars (21, 22) are both placed in said first working position, or whether one is placed in said first working position and the other in said first working position; second working position, or vice versa, or depending on whether both are placed   in said second working position.   3.- sewing machine according to one of the claims-   1 or 2, characterized in that said linkage   (23, 17, 40) essentially comprises at least one slide   bucket (40) axially slidable relative to said   shaft (42) and a driving device (17) for   said slide (40) which is controlled by said unit of   decoding (20, 25) and arranged to place a first   first arm (48) of the slider (40) in one of the three aforementioned working positions in each of which   said arm (48) is pushed against a corresponding surface   first, second or third cam (51, 52, 53).   4. Sewing machine according to claim 3, characterized in that said slide (40) comprises a second arm (55), one end (56) of which is connected to the arm (57) projecting radially from said shaft (42) and makes pivoting said arm (57) about said shaft (42) in relation to the contour of said first, second or third cams (51, 52, 53).   5.- Sewing machine according to any one of   Claims 1 to 4, characterized in that said element   profile (65) has a frustoconical shape and in that said roller (58) is arranged to slide, during a seaming cycle, respectively from an intermediate cross-sectional area to a minimum cross-sectional area and then to a zone of maximum cross-section and return to said intermediate cross section area, or vice versa, or remains always in said intermediate zone, ensuring a transmission of axial movement to said shaft (42) via said arm (57). ); said arm (42)   finally transmitting said axial movement to said   driving dog (15) via said carrier shaft (16).