FR2574017A1 - METHOD AND APPARATUS FOR ULTRASONIC CUTTING AND FIXING, PARTICULARLY FOR SHEET TEXTILE MATERIAL - Google Patents

Abstract

THE INVENTION CONCERNS CUTTING AND FIXING BY ULTRASOUND IN A CUTTING AND FIXING STATION 18 COMPRISING A FINGER RESONANT TO AN ULTRASONIC FREQUENCY AND A WHEEL ARRANGED IN FRONT OF THE SAME; SHEET MATERIAL 12 PASSING THROUGH THE STATION IS CUT AND FIXED IN A MARGINAL AREA ADJACENT TO THE CUTTING LINE AND A THERMOPLASTIC FILAMENT 40 IS SIMULTANEOUSLY BROUGHT INTO THE STATION IN A POSITION SUCH AS FILAMENT 40 MELDS WITH MATERIAL 12 IN THE AREA MARGINAL.

Description

The present invention relates to a method and an apparatus for cutting

  and "fixing" by ultrasound, and more specifically, a method and an apparatus for ultrasonic cutting and fixing for a textile sheet material which is continuously fed to a cutting and fixing station to simultaneously provide a cut edge and fixed on the material to avoid fraying of the wires

  or the formation of a frayed edge.

  The use of ultrasonic energy to simultaneously cut and fix the edge of a plastic or textile material is well known in the state of the art. The patents listed below are representative of this state of the art: Balamuth US Patent No. 3,254,402 June 7, 1966 Deans US Patent No. 3,308,003 - March 7, 1967 Sulzer Swiss Patent No. 439,158 June 30, 1967 Obeda Patent EU N 3,378,429 April 16, 1968 Sager US Patent No. 3,657,033 April 18, 1972 Reifenhauser US Patent No. 3,681,176 August 1, 1972 Obeda US Patent No. 3,697,357 October 10, 1972 Obeda US Patent No. 3,737,361 June 5, 1973 Ries Germany GM 7,401,580 May 2, 1974 Parry US Patent No. 3,852,14 December 3, 1974 Calemard US Patent No. 4,097,327 June 27, 1978 The main advantage of the ultrasonic cutting and fixing process is that the edge textile material, when cut, is simultaneously fixed by the dissipation of ultrasonic energy, thereby preventing the presence of a frayed edge or the fraying of the threads on this material.

257401'7

  In order to successfully apply the ultrasonic process to textile materials, the textile material must contain a significant proportion of

  thermoplastic fibers, typically 50% or more. The material

  thermoplastic layer, under the influence of ultrasonic energy, softens and flows, after which it stiffens when it is no longer subjected to ultrasonic energy, leaving a molten surface in a marginal area

  narrow adjacent to the cutting line.

  It is therefore a main object of this invention to provide an improved ultrasonic cutting and fixing method and apparatus for sheet material which is characterized by a relatively low thermoplastic content or which has a relatively loose texture, or

  which is made of natural fiber, for example cotton.

  Another important object of this invention is to provide an ultrasonic cutting and fixing method and apparatus for sheet material, in which a filament is melted to the sheet material in an area

  margin adjacent to the cutting line.

  Another important object of the present invention

  is to offer a cutting and fixing device by ultra-

  sounds to make an edge attached to sheet material so that the edge is improved and has greater

  resistance to wear and tear.

  Yet another object of the present invention is to provide an ultrasonic finger comprising means for supplying and guiding a filament material over the textile material in the area where the cutting and fixing of the

  textile material must occur.

  As noted so far, the process

  as described above cannot be used successfully when the thermoplastic fiber content drops below the required value or when the sheet material is

of a relatively loose texture.

257 401 7

  According to a first of its aspects, the invention provides a method for providing a finished edge on a sheet material, using an ultrasonic cutting and fixing device, characterized in that it comprises the steps consisting in: implementing an ultrasonic cutting and fixing station comprising a wheel and a finger facing it adapted to be resonant at an ultrasonic frequency; passing a sheet material through said station so that this material disposed between said wheel and said finger is cut and fixed simultaneously in a marginal zone adjacent to said cutting line in response to the fact that said finger is resonant and in contact with the material in sheet passing over said wheel; bringing at least one filament adapted to melt in response to the dissipation of ultrasonic energy delivered by said finger, the sheet material between said wheel and said finger being simultaneously in a position such that said filament melts and fuses with the sheet material in said marginal area, and removing the portion of cut sheet material

  and fixed from the cutting and fixing station.

  According to a second of its aspects, the invention provides an ultrasonic cutting and fixing device for sheet material comprising a cutting and fixing station in the form of a wheel and a finger facing it adapted to be resonating at an ultrasonic frequency to deliver ultrasonic energy on its output surface to the sheet material brought to said wheel, characterized in that, in addition, means are provided for bringing the sheet material into said station, the wheel has a cutting surface and an adjacent fixing surface means are provided for bringing a filament, adapted to melt in response to the dissipation of ultrasonic energy delivered by said finger, simultaneously with the sheet material between said wheel and said finger, this thanks what said cutting surface will cut the sheet material in response to said finger being resonant and in contact with the sheet material

  and said filament will melt and become melted with the material

  leaf riau in a marginal area adjacent to the

  cutting line defined by said fixing surface.

  In other words, the invention proposes the use

  a wire or a filament, preferably of thermo-material

  plastic, which is brought along with the sheet material to the ultrasonic cutting and fixing station to cause the filament to melt and impregnate it into the sheet material in the marginal area adjacent to the cutting line. In this way, the sheet material, if it is of a loose texture, has its edge reinforced, which

  which thereby produces a significantly improved edge

  tive and which is characterized by better resistance to tearing and wear, and, in cases where the material contains less thermoplastic fibers than the required content, or contains mainly natural fibers, such as cotton fibers, the addition of the thermoplastic filament increases the thermoplastic content at the edge to such an extent that a fixed edge can be achieved.

  As will emerge from the description below,

  the filament, preferably made of thermoplastic material, can be either a monofilament or a multifilament, and can be either of the same color as the sheet material, or of a different color from that of the sheet material to give, in this last case, a decorative appearance. The advantage of adding a relatively filament

  end is that the thread flows through the inters-

  sheet material and therefore does not add anything to the thickness of the base sheet material as is the case, for example, in the Swiss patent mentioned above, in which a wide ligating tape is used to cover the ends of cut wires. In addition, the method and apparatus of the invention are particularly indicated for providing a finished edge on a nonwoven sheet material where the fibers are randomly oriented. The method and apparatus of the invention are also applicable to woven materials produced on looms without a shuttle, on which an unfinished edge is obtained, this edge having to be trimmed and finished before the material

in sheet be ready for sale.

  In addition, the invention provides an improvement in the supply of the filament in the area below the ultrasonic finger for contact with the textile material. The filament, although relatively thin, must be positioned with extreme precision in the area below the ultrasonic finger, in front of which is a wheel having the cutting and fixing surfaces. In a preferred embodiment of the invention, the finger is produced with a groove or with an inclined bore at the outlet end of the ultrasonic finger, the

  groove or hole extending in an angular direction

  re from the side of the finger until it ends on the underside

  of the finger which forms the outlet surface in contact with the sheet material to be cut and fixed. The hole is sized to guide the filament material and to ensure that the filament remains precisely located at all times relative to the cutting and fixing surfaces

wheel.

  The invention will be better understood on reading

  the following detailed description in which we

  refers to the accompanying drawings in which: FIG. 1 is a schematic representation of a characteristic apparatus for cutting and fixing by ultrasound; Figure 2 is an elevational view of a characteristic ultrasonic cutting and fixing station; FIG. 3 is a schematic representation of a textile material having a marginal zone adjacent to the cutting line fixed by ultrasound in accordance with the present invention; Figure 4 is a representation showing the section and the attachment of the textile material, which material is disposed between an ultrasonic finger and a wheel; Figure 5 is a representation showing an arrangement of the textile material and the filament disposed between an ultrasonic finger and a wheel before cutting and fixing; Figure 6 is a view similar to Figure 5, but showing a different arrangement; Figure 7 is a representation similar to Figure 5 in which two filaments are used as may be necessary in the case of an ultrasonic slitting apparatus; Figure 8 shows another embodiment in which the filament is guided by a groove in the ultrasonic finger; Figure 9 is a view along line 9-9 of Figure 8; Figure 10 shows another embodiment of the present method and apparatus, and Figure 11 is a schematic view of yet another embodiment of the cutting and cutting apparatus.

  ultrasonic fixation according to the present invention.

  Referring now to the figures, and in particular to Figure 1, the reference numeral 10 designates the end of a loom from which emerges a sheet 12 of textile material which is driven in a way continues by means of suitable and well-known drive mechanisms 14 and 16 through an ultrasonic cutting and fixing station, generally designated by the reference numeral 18. The cut and fixed sheet material is collected on a storage roller 20 while the selvedge 22 is rejected. The ultrasonic cutting and fixing station 18 essentially comprises a support 24 (see also FIG. 2), which supports an ultrasonic conversion unit 26 which

  receives high frequency electrical energy from a gener-

  tor 28 via an electrical conductor 30.

  The converter unit 26 contains a piezoelectric transducer material for delivering, in response to a power supply

  high frequency electrical input, mechanical vibration

  ques a finger 32 sized to be resonant the

  along its longitudinal axis at a high frequency predeter-

  undermined. The conversion unit 26 and the finger 32 are designed to be resonant at a high ultrasonic frequency, the characteristic working frequencies being 20 kHz and kHz. The other suitable frequencies are in

  a range between 16 and 100 kHz.

  The outlet surface 34 of the finger is located in

  face of a dial 36 which will be described in more detail below

  after. The wheel can be rotatable, or, as used in the present invention, locked in rotation by a screw placed in its center, and it is indexed to

  present with the finger a new portion of peripheral surface

  risk whenever a previously exposed portion of the surface has become dull or damaged. Either the wheel is spring-mounted as shown in US patent 4,097,327 mentioned above, or the conversion unit is pushed against the wheel by a spring as shown in US patent 3,734,805. The cutting and fixing station, comprising the support 24, the conversion unit 26 the finger 32 and the dial 36 as well as the electric generator 28, is a commercial unit and is available under the name of "On-Loom Ultrasonic Slitter "(Ultrasonic slitter on loom) at Branson Sonic Power Company, Eagle Road, Danbury, Connecticut 06810, United States of America, and it is described in the Branson Data Sheet PW-36 (Branson technical sheet PW- 36). A similar unit is also set out in patents CH 439,158 and US 4,097,327

mentioned above.

  In the present invention, a filament 40, which is preferably a thermoplastic filament, either a monofilament or a multifilament, is unwound from a reel 42 and delivered via the guide rollers 44, 46 and 48 to the station of ultrasonic cutting and fixing 18 together with the sheet material 12 to be melted with the sheet material in the area

  margin adjacent to the cutting line.

  Figure 3 shows the result of this arrangement. The reference numeral 12 denotes the sheet material, for example a loose weave or a randomly oriented fiber sheet, which has been cut to produce an edge 50. The marginal area 52 adjacent to the cutting line is filled with the thermoplastic material 41 of the filament 40 and the entire area 52 is melted as a result of the dissipation of the ultrasonic energy delivered by the%: finger 32. In response to the dissipation of ultrasonic energy, the thermoplastic fibers of the sheet material 12 and the filament added thermoplastic 40 soften, flow under the influence of the pressure exerted, after which they harden when they move away from the cutting station and

  fixing to thereby form a rocket material. The margi-

  melted nale is a relatively narrow area and has a finished edge that is not subject to a frayed appearance or fraying of the wires. This phenomenon has been described in

  detail in US Patent 3,378,429 mentioned above.

  Figure 4 shows the structural details of the finger and the wheel facing it with the sheet material which is interposed during the cutting process

  and fixing. The wheel 36 has two fixing surfaces

  frustoconical tion 54 and 56 and a raised cutting surface located centrally 58 in the form of a central edge. The surfaces of the thumbwheel face the flat outlet surface 34 of the finger 32. As stated above, the thumbwheel and the finger are pressed against each other by suitable pressure means, such as the pressure d '' a spring or the combination of the pressures of a spring and a fluid, and, moreover, the front surface of the finger, when the latter is made resonant, performs an alternating movement as it approaches and moves away from the wheel, which movement is responsible for the cutting phenomenon and the dissipation of energy, which is transformed into heat in the sheet material 12 to cause softening and melting of the thermoplastic material. As can be seen in FIG. 4, the sheet material exposed to the fixing surface 54 of the wheel 36 has a large amount of molten material due to the addition of a filament 40, while the sheet material 12 in contact with the fixing surface 56 has a lower amount of molten material because only the thermoplastic fiber content of the sheet material takes a molten state. The material 12

  on the fixing surface 56 is rejected with the selvedge 22.

  It will be readily apparent that the present device in which a filament of thermoplastic material is added is eminently suitable for producing a cut and fixed edge on a textile material which contains only a small proportion of thermoplastic fibers or when a loose weave has to be cut and fixed, because, in the latter case, the thermoplastic filament added in the fixing station will be pressed into the interstices of the material

  sheet, filling the spaces with thermo-material

  plastic, and therefore producing a reinforced marginal area adjacent to the cutting line. In addition, the present invention can also be used to make an edge

  cut and attached to sheet material comprising mainly

  of natural fibers, such as cotton, which

  fibers are not subject to softening or

  fusion under the influence of ultrasonic energy.

  Figure 5 shows the ultrasonic finger 32 and the dial 36 which faces it separated from each other before cutting and fixing by ultrasound. The filament 40 is delivered to the fixing surface 54 of the wheel 36 and it is in contact with the sheet material 12 (in contrast to FIG. 1, the spool 42 and the roll of

  guide 44 are arranged under the sheet material 12).

  In Figure 6 the arrangement corresponds to the representation of Figure 1 in which the filament 40 is disposed between the sheet material 12 and the outlet surface 34

  of finger 32. Reacting to means of pressure (not shown

  smelled) and on application of the ultrasonic energy by finger 32, the molten state shown in FIG. 4 is caused, giving the sheet material a cut and fixed edge as

shown in figure 3.

  Figure 7 shows another modification. Two filaments 40A and 40B are brought to the wheel 36, each filament being in contact with a respective fixing surface 54 and 56. In this way, the sheet material on each side of the cutting edge 50, in FIG. 3, will have a fixed marginal area 52, as may be necessary in a slitting apparatus in which a wide sheet material is slit into narrower tapes and the edge of

  each ribbon should have a finished appearance.

  In FIG. 10, a filament 40 is brought to the central cutting surface 58 of the wheel 36, providing

  thus substantially equal amounts of the thermo material

  plastic added to each side of the cutting edge as a result of the softening of the material which is crushed

  two sides. Figures 8 and 9 show another modification.

  tion in which the filament 40 is brought through

  diary of guide means 60 in the outlet surface of the finger 32 to the cutting and fixing surfaces. The guide means comprise a groove arranged on the surface

lower finger.

  It should be noted that the filament added to the sheet material at the fixed area can be either the same color as the sheet material, or a different color to give a decorative appearance. In addition, the sheet material may be in a single layer as shown, or may be in several layers which then become welded together at the cut edge and in the marginal area adjacent to the cutting line responsive to energy dissipation. ultrasonic and melting and

  melting of the thermoplastic material.

  Figure 11 shows another different embodiment.

  invention rent. A finger 32A is coupled to the convert-

  26, showing the mechanical vibrations on the outlet surface 34A of the finger. As shown in FIG. 11, the front end or outlet end of the finger 32A is a part of a removable endpiece 66 which is screwed to the finger by a bolt 68. The endpiece 66, as it easily appears, is easily replaceable when it is worn out or when it needs to be changed. The endpiece 66 is produced with a bore 70 which is inclined relative to the longitudinal axis of the finger 32A to allow the filament 40 to be brought from the outside of the finger onto the workpiece 12,

  The drilling ends on the outlet surface 34A of the finger.

  In a typical example, the material 12 is a mixture of polyester fibers or natural fibers and the material of the filament 40 is nylon, polypropylene, polyethylene or polyester, having a diameter included

  between 0.13 and 0.4 mm. The hole 70 has a cross section

  circular dirty to receive a rondo filament The replaceable tip 66 has the advantage that several tips can be provided to adapt to different diameters of filaments and the drilling has the advantage that a guide

  extremely precise filament is made.

  As can be seen in Figure 11, the sheet material is passed through the gap between the finger and the wheel in the direction indicated by the arrow. The portion of filament fused to the sheet material 12 causes

  advancement of new filament material through the hole

  ge 70 as the sheet material advances through the gap. The central axis 78 of the finger 32A is slightly offset relative to the axis 80 of the disc-shaped wheel to allow the filament 40 to be brought above the wheel in front of the point of maximum compression, and, consequently, from the point of maximum dissipation of energy, that is to say the zone where the spacing between the outlet surface 34A and the wheel 36 is minimal. This arrangement ensures that the filament is first brought to the sheet material and then melted with the sheet material when the material passes through the cutting station and

of fixation.

  While we have described and represented here several

  preferred embodiments of the invention and that some

  no modifications have been indicated, it will be obvious to those skilled in the art that further modifications and modifications can still be made without differing from

  the scope of the applicability of the present invention.

-13-

Claims (11)

  1. Ultrasonic cutting and fixing apparatus for sheet material comprising a cutting and fixing station in the form of a wheel and a finger facing it adapted to be resonant at an ultrasonic frequency to deliver on its surface output of ultrasonic energy to the sheet material fed to said wheel, characterized in that further: means are provided for feeding the sheet material into said station; the wheel has a cutting surface and an adjacent fixing surface; means are provided for bringing a filament, adapted to melt in response to the dissipation of ultrasonic energy delivered by said finger, simultaneously with the sheet material between said wheel and said finger, whereby said cutting surface will cut the sheet material in response to said finger being resonant and in contact with the sheet material and said filament will melt and melt with the sheet material in a marginal area adjacent to the line   cutting defined by said fixing surface.   2. Apparatus according to claim 1, characterized in that the filament is brought disposed between said wheel and sheet material.   3. Apparatus according to claim 1, characterized in that the filament is brought disposed between said finger and the sheet material.   4. Apparatus according to claim 3, characterized in that the finger has means on its surface for   outlet to guide the filament on the sheet material.   5. Apparatus according to claim 4, characterized in that the means for guiding the filament comprise a groove.   -14- 6. Apparatus according to claim 3, characterized in that the means for guiding the filament comprise a hole extending from the side of the finger, inclined in an angular direction relative to the longitudinal axis of said finger, up to the surface of exit of said finger   to guide the filament over the sheet material.   7. Apparatus according to claim 1, characterized in that the wheel has a pair of fixing surfaces and a cutting surface arranged centrally, and in that two filaments are delivered in a position   as it causes the processing of a resilient filament   pective by a respective fixing surface.   8. Apparatus according to claim 1, characterized   in that the finger is resonant at a predetermined frequency-   mined in the range from 16 KHz to 100 KHz.   9. Apparatus according to claim 6, characterized in that the bore is arranged in a tip mounted so that it can be replaced forming a part of said finger. 10. Apparatus according to claim 6, characterized   in that the bore is of circular cross-section   laire. 11. Apparatus according to claim 6, characterized   in that the thumb wheel has at least one fixing surface   tion and a cutting surface, said drilling ending to bring the filament onto the portion of material in   sheet disposed above said fixing surface.