DE7033547U - TRIMMING OR CUTTING DEVICE FOR SEWING MACHINES. - Google Patents

Description

PATENT LAWYERS

DR. E. WIEGAND DIPL-ING. W. NIEMANN DR. M. KÖHLER DIPL-ING. C. GERNHARDT

MÖNCHEN HAMBURG

PHONE: 3953U 2000 HAMBURG 50, 7th Sept. 197ο

TELEGRAMS: CARPATENT CON IGSTR ASS E 28

W.24279 / 7Q VH

The Singer Company, Elizabeth, New Jersey (V.St.A.)

Trimming or cutting device for sewing machines.

The invention relates to a trimming or cutting mechanism for sewing machines and in particular a trimming or cutting mechanism for separating the lower fabric layer at a point near the seam line when it is being hemmed or sewn.

Certain operations in the manufacture of textile products require simultaneous sewing of the seam and severing or cutting off the marginal edge of one layer of the sewn material. During later operations that are performed on the workpiece, the wider one becomes Edge wrapped around the severed edge and an extra line of stitching is applied on it for such a good-looking, to create a strong and firm seam in which each of the severed edges is hidden. With sewing machines, which are adapted to these operations, it is desirable for the operator to be able to use the facility to have the cutting effect of the separating blades resp. adjust the separator sheet for different purposes, for example to cut different material thicknesses,

to coordinate the cutting tool with the stitch length etc. For the highest working speed of the sewing machine is it is necessary, however, that under these circumstances the total movement or the total stroke of the cutting tool is as short as possible in order to reduce the vibration to a minimum. The present invention enables the operator to lift or move the cutting blade or to adjust the cutting blade and at the same time to change its vertical upward movement, so that essentially the overall change in stroke or movement contributes to increasing the cutting action of the blade.

The main object of the invention is to provide an improved trimming or cutting mechanism for use to create in a sewing machine, which is a marginal edge of a workpiece to be sewn simultaneously with the sewing can cut off the workpiece.

Another object of the invention is to provide in a sewing machine a trimming or cutting mechanism in which the movement or stroke of the trimming or cutting blade can be adjusted by the operator's choice to suit various working conditions, and in which the separating or cutting blade can be completely stopped while the machine continues sewing.

Another object of the invention is to provide a separating device which can be used in a sewing machine can be used, in which the vertical upward movement of the separating or cutting blade is automatically adjusted when the stroke of the blade by the operator is adjusted so that essentially the entirety of the increase in the stroke contributes to the cutting effect To increase the separating or cutting blade, whereby an idle movement or an unnecessary movement of the sheet and a Vibration is reduced to a minimum.

The solution according to the invention is that cams or template parts are provided, which by a loading

Serving at choice are actuated to a control shaft press to adjust the stroke of the trimming or cutting blade to the type of workpiece to be cut and make the vertical upward movement of the trimming or cutting blade at the same time. The trimming or cutting blade is driven by a drive lever from an eccentric on the base or lower shaft. The drive lever is arranged displaceably at one end in a support frame or in a frame. A movement of the steering shaft changes the position of the articulation point of the separation or Cutting blade, thereby changing the vertical upward movement, and continues to change the direction of oscillation of the drive lever by changing the angular position of the support frame to thereby increase the stroke or the movement of the trimming or cutting blade.

The following is an embodiment of the invention explained as an example with reference to the drawings. Fig. 1 is a perspective view of the trim or Cutting mechanism according to the invention, which is partially in section and in the maximum Cutting position is shown.

Fig. 2 is a cross-sectional view through the base of a sewing machine incorporating the invention, taken along line 2-2 of Fig. 1 and showing a portion of the stand in side elevation.
Figure 3 is a cross-sectional view through the base

the sewing machine according to line 3-3 of FIG. 1. Figure 4 is a cross-sectional view through the base of the sewing machine taken substantially along line 4-4 of Fig. 1 and shows the fabric sheet diverter used in the trimming or cutting mechanism.

Figure 5 is a bottom plan view of the sewing machine with part of the feed mechanism broken away and part of the rack or housing

is shown in section.

Fig. 6 is a bottom plan view of the trimming or cutting blade and its support members as shown in Fig. shown, but shown in a separate position for clarity.

Fig. 7 is an enlarged partial top plan view of the stitching area of the sewing machine showing the location of the trimming or cutting blade in relation to it and still shows the ply separator in dashed lines.

Figure 8 is a view similar to partial top of Fig. 7, but in an even larger one Scale in which the accessory plate has partially broken away.

Fig. 9 is a cross-sectional view taken along line 9-9 of Fig. 8 showing the trimming or cutting blade at the top of its stroke bv-tf, its movement again before making a cut and continues to give the layer separator or the layer separator again, the between the two layers of a workpiece is arranged.

Fig.Io is a cross-sectional view similar to that of FIG Fig. 9 according to line lo-lo, which, however, the Trennbzw. Cutting blade in its position after Cutting the lower layer of the workpiece reproduces, and the

Figures lla to lld are front views with partial broken parts and indicate the position of the separating or cutting blade relative to the needle plate of the sewing machine for various settings of the lever controlled by the operator again.

Fig. 11a shows the non-cutting position.

11b shows the separating or cutting blade in FIG

Above - UTva in the lower position of its hub for the first position.

Flg. lic shows cisu; Separating or cutting blade in the top and in the lower position of its stroke door the second cutting position, and

Pig. Hd shows the separating or cutting blade in the top and bottom of its stroke for the maxima le cutting position.

In the drawings, the invention is shown applied to a zigzag sewing machine which has a base

10 and has a base plate 11, on the upper Area an accessory plate Ha and a throat plate 12 are attached, with the usual openings or holes for Adaptation to a knife gate valve 1-3 provided 1st. A stand 14 (FIG. 2) extends from the base Io at one end above, the upper end of which has an overhanging machine arm (not shown) that extends above the base plate

11 extends and terminates at its outer end (not shown) in a head, as in the relevant art is known. In the head is for a back and forth movement in its longitudinal axis and for a zigzag swinging movement a needle bar 15 which is slidably mounted and which carries a needle 16 at its lower end. A needle swing out mechanism Of the usual design, the needle 16 can pivot or swing out in a longitudinal direction of the base Io permit. Furthermore, a push rod 17 is mounted in the head, which at its lower end a Carries presser foot 18, which works together with the knife pusher IJ, in order to hold the work piece in the usual way in a direction transverse to the base and to present or to advance. A slotted needle hole 12a, which extends in the longitudinal direction of the base, is in the throat plate 12 provided. A rotating looper works with the needle in the usual way for the production of lock stitches 19 together, of a shaft 2o by means of a

(not shown) gear within gear box 21 and 22 (Fig. 5) is driven. A rotatable base or sub-shaft 23, which drives the gearbox, derives its movement from a pulley 2k at the right end (as viewed in FIG. 5), which in turn is supported by a belt 25 from a main drive shaft (not shown) in FIG temporal relationship to the needle bar. The feeder 13 is given a feed movement by means of feed rods 2b, 26a which are connected to a triangularly shaped feed rod 27 which is driven by the base or lower shaft 23 by means of a feed rocker arm 28. An eccentric (not shown) on the base or lower shaft 23 gives an arm 29 a movement, which in turn drives a swing arm 28. An eccentric (not shown) on a shaft stump 30 gives the feed rods 26, 26a a feed stroke movement. Since the advancing mechanism is not part of the present invention and is well known in the art, it need not be described in further detail.

In the following, the trimming or cutting mechanism according to the invention will be described in particular with reference to FIGS. As can best be seen from FIGS. 1 and 3, an eccentric 31 and a flywheel 23a are arranged on the lower or base shaft 23. An eccentric bracket connection 32, which has a control rod extension 33, transmits an oscillating movement to a drive lever 34. The drive lever 3 ^ contains two parallel parts or wall sections 35 and 35a which are connected to one another by a lower section 36 and two stiffeners 37 and 37a. The control rod extension 33 is bolted between the wall sections 35 and 35a. At each end of the drive lever J> k there is a forked part or fork 38 or 39, respectively, between the wall sections 35 and 35a. Inside the fork 38 is a cylindrical sliding part 4o with a bore kl.

camps. A pin 42, which is inserted in a yoke part or support frame 43, can pass through the bore 4l in the slide part 4ö. The support frame Kj is essentially a box-shaped element, one end of which is open for the drive lever 34 to pass through. As can be seen from FIGS. 1 and 5, shafts 45 and 46 are connected to the end walls 44 and 44a of the support frame 43 and are mounted within the base Io of the machine, for example at 4γ and 48. At 39a within the fork 39 of the drive lever 34, a crank arm 49 is mounted, which is provided at its free end with a slotted socket part which is firmly connected by means of a screw 51 to a short, reciprocating shaft 52 or oscillating shaft, which has a Has stop member 53 which is mounted within the housing of the machine, as shown at 54 in FIG. On the shaft 53, the hub of a crank arm 55 is fixed, whose free end is bolted at 56 to a lever 57 (Fig. 4). The lever 57 is in turn connected by a bolt at 58 to an arm 59 of an angle lever 60 which is pivotably mounted at the pivot point 61, as will be described later. Another arm 62 of the angle lever 60 is bent away from the pivot point 6l at 63 at a right angle and has an upward part 64 there. A trimming or cutting element 65 is connected to the part 64, for example by screws 66 and 67. A slot 67a in the trimming or cutting element 65 enables adjustment of the lateral movement of the trimming or cutting mechanism of the trimming or cutting element 65 (FIG. 8).

In the base plate 11 at the end of the stand of the machine, a pin 68 (Fig. 5) is mounted, the upper end of which is a Has disc 69 (Fig. 2) which is connected to it by means of an adjusting screw 7o. A lever 71> which has a control button 72 to be actuated by the operator is fastened within the disk 69. The pin 68 goes through

a plate 73 which rests on the base plate 11 therethrough. Below the base plate 11, the pin 68 is fastened in a template or cam element 74 (FIG. 1), and is fixed on its hub by means of an adjusting screw 75. A cam track 76 is located on the cam element 74 formed, which a series of grooves 76a, 76b, 76c and 7od according to the stroke of the selected trimming or cutting element 65 contains. The groove 76d corresponds to the non-cutting position or the setting in which the trim or The cutting blade does not swing or swivel, Of course, within the scope of the present invention, any Number of grooves, more or less than four, can be used.

In contact with the cam track 76 is a trailing pin 77 (FiF · 1), which is connected to a trailing arm 78 is firmly connected, the lying on its ic * ^ '.--- ^ The end of a slotted bushing 79 is on vrc-is. The socket 79 goes around a control shaft 80 and is attached to it by means of a screw 8l in such a position that the follower pin 77 is always in contact with the cam track 76. The control shaft 80 continues to go through the slot sleeve 82 of a crank arm 83 therethrough, and the Slotted socket 82 is attached to control shaft 80 by means of a screw 84 (Fig. 3). The lower end of the crank arm 83 is at 85 by a pin at one end a lever 86, the free end of which at 87 is connected to the support frame 43 below the shaft 46 by a pin (Fig. 1) is connected. In this way, there is a between the shaft 46 and the connection at 87 on the support frame 43 Created with few moments. It can therefore be seen that movement of the control button 72 by the operator causes that the control shaft 80 rotates in a given direction, whereby the support frame 4jJ is caused to its angular position to change.

Furthermore, on the control shaft 80, for example by a

70335 ^ 715.4.71

Locking part 88, a lever element 89 attached (Fig. 1). It can be seen that the locking part 88 has two approaches Qo and Q? (Fig * 6), through which a screw 92 passes through. A finger 93 on the upper end of the locking part 88 is forcibly pressed into engagement with a step 9 ^ on the lever member 89 when the screw 92 in the approaches 90, 91 is tightened. The angle lever 60 is articulated at pivot point 6l between lugs 95 and 95a of lever element 89 for the purpose of pivoting movement relative to it (Figures 1 and 2). A support part 96 at the lower end of the base Io is by means of a nut 97, for example connected to a cylinder 98. Inside cylinder 98 a spring (shown clearly) presses a pin 99 against the lower end of the lever element 89 'around him in this way to push up. The control shaft 80 passes between the slotted bushing 82 and the lever element 89 and is arranged concentrically with the reciprocating shaft 52 and works to the purpose of reciprocating shaft 52 To store pivoting movement.

A spring loo (Fig. 1), which e.g. by a pin Io1 attached to the base Io of the machine at one end is, stands with a pin lola on the support frame 4) in Engages so as to move the support frame 43 towards its maximum To press inclined position, as shown in Fig. 1. This, in turn, results in the endeavor, the trailing pin 77 to hold against the cam track 76 by means of the lever 86 and the crank arm 83. At the end of the stand of the base Io is a bearing part Io2 below the base plate 11 on the base Io by means of a screw I03 attached. A slot Io4 in the bearing part Io2 enables a lateral displacement of the bearing part Io2 relative to the base lo. An upstanding part I05 of the bearing part Io2 receives the end of the control shaft 80 within an opening therein. To one to be described later Purpose pushes a spring between the part I05 and I06

- Io -

of the slotted sleeve 79, the control shaft 80 and the elements attached to it to the left as viewed 5. Sockets Io7 and I08 (Fig. 5) in the base Io Machine and the reciprocating shaft 52 carry the Rotatable control shaft 80 which passes therethrough.

As best seen in Fig. 5, the cam track 76 does not extend completely around the cam element "Jh, but terminates at edges I09 and Ho. A stop pin 111 protruding from the base Io of the machine can extend into it 5 from the edge I09, whereby the movement of the cam element 74 between these edges Io9 and Ho is limited. The pin 111 stands with the edge Io9 at the maximum cutting position, as shown in FIG Fig. 5 is shown, and with the edge Ho in the non-cutting position engaged, so that the operator can comfortably go either in one or the other of these end positions.

At a shoulder on the base plate 11, e.g. by means of an adjustable screw 112, the work piece layers are attached separating part or a layer separating part 113 attached which, as can best be seen from FIGS. 9 and Io, to this effect works to separate the upper layer from the lower layer when the latter is severed or cut through. As can be clearly seen from Fig. 8, the layer separating part 113 a cut-out part 114 to make a free one To allow space for the trimming or cutting blade during the upward movement of this blade. Furthermore is a conically tapered or pointed upper surface 115 and a hook-shaped part II6 on the layer part 11J5 is provided, thus the same between the upper layer 117 and the lower layer II8 as close as possible to the stitch formation point without deflecting the top sheet in such a way that the sewing process is disturbed.

The trimming or cutting element 65 includes a trimming

or cutting blade 119 having a wedge-shaped cutting edge. The separating effect takes place through a scissors-like j Movement of the cutting edge 12o against a shear blade 121, such as

it is shown in Figures 9 and Io. The tension provided by the spring Io6 (Figures 1, 5) holds the cutting blade 119 against the shear blade 12o for proper cutting. The movement of the separating or cutting blade 119 takes place in a vertical plane which is perpendicular to the textile material to be cut through. This plane is the paper plane of FIGS. 11a to 11d. The oscillating movement of the angle lever 6o about the pivot point 6l also produces a movement of the cutting blade 119 on a somewhat arcuate path within this vertical plane.

With the present embodiment, when the stroke of the cutting blade is set by the operator, the Upward movement of the toggle element 89 changed, whereby the position of the pivot point 6l relative to the throat plate 12 is changed. The center of vibration of the cutting blade 119 is therefore changed simultaneously and automatically with the stroke. In Figures 11b to Hd, the position of the Cutting blade in full lines at the upper end of his Stroke and shown in dashed lines at the lower end of its stroke. It can therefore be seen that the lower end of the stroke is always at the same level, which is also the zero stroke position for any selected Hub is. Adjusting the stroke therefore increases or decreases the effective stroke or cutting action of the cutting blade 119, as a result of which an idle movement of the cutting blade 119 is essentially avoided.

If the operator wishes to select a particular cutting action of the cutting blade 119 while working, moves He just presses the control button 72 until the trailing pin 77 with one of the grooves 76a, 76b or 76c on the cam track 76 engages. Displays can be provided on the base plate 11 of the machine in order to

display the selected hub. Since the follower arm 78 is mounted on the control shaft 80, it therefore rotates this shaft by an angle that is determined by the groove or the selected stroke. Since the crank arm 83 and the lever member 89 are also mounted on the control shaft 80, they are rotated simultaneously with her.

A movement generated by the crank arm 83 is transmitted to the support frame 43 by the lever 86, thereby causing the support frame 43 and the pin 42 to move due to the bearing relationship of the shafts 45 and 46 assume a predetermined angular relationship in the support frame 43 .

A rotary movement of the lower or base shaft 23 is converted into an oscillating movement by the eccentric 31, the bracket connection 3 ^ and the control rod extension 33. The drive lever 'j> k is always given an oscillating movement in this way ^, but the oscillating path or the Vibration path changeable. When the pin 42 is in the neutral or in the vertical position, the sliding part 4o and infox the drive lever 34 always run empty, along the pin 42 up and down and around 39a with the crank arm 49. As a result, no horizontal movement is transmitted to the crank arm 49 for pivoting the reciprocating shaft 52. If the pin 42 is bent in a radius or curved equal to the countries ae of the drive lever 34 is, at all ktine horizontal movement would be transmitted to the crank arm 49th However, if the support frame 43 and therefore the pin 42 are arranged at an angle to the vertical, the guide part 4o has a horizontal component. The drive lever 34 is therefore given this movement component, which in turn pivots the reciprocating shaft 52 by the crank arm 49, which in turn pivots the angle lever 60 about the pivot point oil by means of the lever 57. The swiveling or oscillation amplitude, which is due to the

and outgoing wave 5 ·? and therefore onto the cutting blade 119 is transmitted, is cianer ^ urch the angular relation of the Support frame 4j5 as set by the control shaft 8o has been controlled.

The angle through which the lever element 89 is rotated determines the upward position of the pivot point 6l and therefore the Center of oscillation of the angle lever 60 and the cutting blade 119.

When it is desired to sew without trimming or cutting, the operator selects the groove 76d which is the support frame 43 and the pin 42 adjusts in the vertical direction. In this position no horizontal movement component is transmitted to the crank arm 49 and the cutting blade II9 does not swing back and forth. In this position, the control shaft 80 also lowers the cutting blade II9 into that in FIG. 11a position shown.

The timing of the rocking or pivoting movement of the cutting blade 119 is such that it moves upward, when the needle 16 is driven upward, as shown in Fig. 9, and it moves downward, around a marginal edge 122 of the lower layer to be severed when the needle l6 is driven downward, as can be seen from Fig. Io.

Claims (2)

Protection claims. 1. Sewing machine with a housing, with stitch-forming devices including a reciprocating needle which is arranged in the housing at a stitch-forming point for sewing, with a rotatable base shaft driven in relation to time to the reciprocating movement of the Naiel, and with a trim - or cutting mechanism, characterized by a manually operated control device (72, 71, 68, 74, 77, 78, 8o, 85, 86, 4 ^, 88, 89, 60) for changing, if necessary, switching off the stroke of a cutting blade (119 ) of the trimming or cutting mechanism during the sewing process, as well as by a drive (25, 3> 1, 32, jn _t 4 ^ 49 ₁ 52, 55, 57, 60) actuatable by means of the base shaft (2p) for the movement of the cutting blade (119). 2. Sewing machine according to claim 1, characterized in that the trimming or cutting mechanism comprises: a cutting blade (119) which is arranged to cooperate with a shear blade (121) in the vicinity of the stitch formation point for cutting through parts of material, a control device for changing the Stroke of the cutting blade during sewing of the machine, a control shaft (80) rotatably arranged in the housing, a cam element (74) mounted pivotably on the housing, a follower part (78, 77) mounted on the control shaft (80), which is connected to the cam element (74) is held in engagement, a device to be operated by the operator (72, 71, 68, 69) which is connected to the cam element (74) for its optional pivoting and for rotating the control shaft (80) by a controllable amount , a lever element (89) attached to the control shaft (80), an angle lever (60) pivotably attached to the lever element (89), elep to which the cutting blade (119) is attached e device (jjl, 32) for converting the rotation of the base shaft (23) into an oscillating movement, one with the Umwanct- treatment device (31, 32) pivotally connected drive lever (34), a reciprocating shaft (52, 53), a first and a second crank arm (49, 55), which on the back and the forward shaft (52, 53) are attached, the first crank arm (49) being pivotable with the drive lever (34) and the second crank arm (55) is operatively connected to the bell crank (60), one in the housing for pivoting movement mounted support frame (4-3) with connected to it, limited movable sliding part (4o) for Pest lay the oscillation trajectory of the drive lever (34) and a fixed on the control shaft (80) with the support frame (43) pivotally connected means (82, 83) for changing the angular relationship between the support frame (43) and Drive lever (34) when turning the control shaft (80).